* * * * * * * * * *

The following parts lists and substitution parts was compiled by lancecriminal86 over the course of a LOT of research. Read up and pay attention!

Below are the 100% .mil-spec parts lists to build a true SPR or Mk12 clone. Some of these parts are no longer manufactured and will require much effort and money to locate through forums and online brokers. Keep in mind the rifles were built off donor M16A1s, hence the prevalent A1 parts in the lower receivers and the BCGs. They were also first configured using parts available from 1998-2004, and most are inferior in some ways to newer designs. If this bothers you too much, STOP NOW.

The rifles were issued as a kit in a Pelican 1700 case with cutouts. The kits included the rifle with suppressor, optic, bipod, an Eagle TAS-1 UMSS sling (unobtanium and also absolute crap), with a Dewey 1-piece cleaning rod plus Otis cleaning kit, and a cutout for magazines. An operator's manual was also included, however these have not been officially released for public consumption. However, the manuals are out there, and some companies building Mk12 uppers include one. Whether these are official .mil operator's manuals or specially made is currently unclear as the manual itself still contains language that it is not for distribution.

- Alternate .mil-spec parts due to NFA, NLA parts, or changes in name/markings for current production in [brackets]

- Extra notes about parts or availability are in (parenthesis)

LOWER
Lower receivers were standard across the SPR/Mk12 variants and the only variations would be between grips, stocks, and buffers. Most were marked either Colt or GM Hydramatic. All other parts were the same in regards to the lower parts. One caveat is the trigger, as the program originally selected the Knight's Armament 2-stage Full Auto Match trigger. Later on, some issues regarding negligent discharges occurred, and Geissele SSF triggers ultimately found their way into the Mk12 family. Whether 100% of all Mk12s eventually received the Geissele trigger isn't clear, so either is acceptable.

• Lower: M16A1 pattern [Nodak Spud NDSA1 or 80% re-profiled/finished/engraved]
• Trigger: Knight's 2-Stage Full Auto Match Trigger or Geissele SSF [KAC semi-auto Match or Geissele SSA/SSA-E]
• Grip: A1, A2, ERGO Original
• Stock: Originally issued with A1 stocks, both solid D and trapdoor E types; as A1 stocks dwindled, A2 were used; ModH rifles rebuilt with Ace SOCOM stocks
• Small parts: Standard M16A1 parts
  
  

UPPER
The upper receivers, which ultimately differentiate the four variants of the Mk12, have the most variation between each other.


Early SPR/Mod0

• Upper: Colt, Diemaco, or Armalite marked, flat top, M4 feed-ramps
• Barrel: Douglas 416r SS, 18" SPR contour, 1/7 twist, flats milled for PRi FSB (Compass Lake, Centurion Arms, High Caliber Sales, and PRi can all supply barrels that meet the appropriate spec minus FSB flats)
• BCG: Colt M-16
• Handguard: Precision Reflex Gen I carbon fiber free-float Handguard, rifle length (identified by button-head screws and one vent hole near barrel nut on lower half; no heat shields)
• A.R.M.S. #38 SPR MOD Sleeve (either the PEQ version or with uneven spacing on the front  but not the full 1913 railed version)
• FSB: PRi early folding front sight base and gas manifold, set-screw, with elevation wheel
• Charging handle: PRi Gas Buster M-84 with military latch
• Muzzle device: OPS Inc 12th Model brake/collar, and 12th Model suppressor [Allen Engineering AEM5 and brake/collar]
• Rear iron sight: A.R.M.S. #40
• Scope rings: A.R.M.S. #22 Medium rings, #22 Tactical Ring Cap and #22 Tactical Ring Rail (rings should not include "lever-stop" hump as produced later by A.R.M.S.)
• Optic: Leupold Vari-X III 3.5-10x40mm LR, M3 turrets, illuminated Mil-Dot reticle (use .308 turret) [Leupold LR/T 3.5-10x40 LR, M3 turrets, Illuminated Mil-Dot reticle]
• Bipod: Versa-Pod with A.R.M.S. #42, or a Harris with A.R.M.S. #32 (Versa-Pod far inferior to Harris)

Late Mod0

• Upper: Colt or Diemaco marked, flat top, M4 feed-ramps
• Barrel: Douglas 416r SS, 18" SPR contour, 1/7 twist, flats milled for PRi FSB (Compass Lake, Centurion Arms, High Caliber Sales, and PRi can all supply barrels that meet the appropriate spec minus FSB flats)
• BCG: Colt M-16.
• Handguard: Precision Reflex Gen III carbon fiber free-float handguard, rifle length
• A.R.M.S. #38 SPR-PEQ-2-3 Sleeve
• FSB: PRi folding FSB, set-screw, .750 (original production had PRi's full address engraved on sight tower; those engraved with "PRi USA" are later manufacture)
• Charging handle: PRi Gas Buster M-84 with military latch
• Muzzle device: OPS Inc. 12th Model brake/collar, and 12th Model suppressor [Allen Engineering AEM5 and brake/collar]
• Rear iron sight: A.R.M.S. #40
• Scope Rings: A.R.M.S. #22 Medium rings (rings should not include "lever-stop" hump as produced later by A.R.M.S.)
• Optic: Leupold 3-9x36mm TS-30, Mk4 MR/T 2.5-8x36mm TS-30A2, M2 turrets with Mk262 BDC, illuminated TMR reticle
• Bipod: Harris with either A.R.M.S. #32 or KAC RAS bipod adapter

SPR/A, SPR/B, Mod1

• Upper: Colt or Diemaco marked, flat top, M4 feed-ramps
• Barrel: Douglas 416r SS, 18" SPR contour, 1/7 twist, flats milled for PRi FSB (Compass Lake, Centurion Arms, High Caliber Sales, and PRi can all supply barrels that meet the appropriate spec minus FSB flats)
• BCG: Colt M-16
• Handguard: Knight's Armament M4 Match FF RAS, rifle length (now called the SR15/16 Match FF RAS)
• Gas block: NSWC Crane pattern (Badger Ordnance parkerized/NSN version is correct, has open front of gas tube hole)
• Charging handle: PRi Gas Buster M-84 with military latch
• Muzzle device: OPS Inc. 12th Model brake/collar, and 12th Model suppressor [Allen Engineering AEM5 and brake/collar]
• Scope rings: A.R.M.S. #22 High rings (A.R.M.S. rings should not include "lever-stop" hump as produced later by A.R.M.S.)
• Optic: Leupold Mk4 MR/T 2.5-8x36mm TS-30A2, M2 turrets with Mk262 BDC, illuminated TMR reticle or NightForce 2.5-10x24 (optionally with NightForce rings)
• Bipod: Harris with KAC RAS bipod adapter (BRM-S, A.R.M.S. #32 could still optionally be used)

ModH, Mod "Holland"

• Upper: Colt or Diemaco marked, flat top, M4 feed-ramps
• Barrel: Noveske 16" Recon, mid-length gas system, profiled for OPS Inc. 12th Model brake/collar (will require aftermarket contouring of most barrels)
• BCG: Colt M-16
• Handguard: Precision Reflex Gen III carbon fiber free-float handguard, FDE, rifle length
• Charging handle: PRi Gas Buster M-84 with military latch
• Muzzle Device: OPS. Inc. 12th Model brake/collar, and 12th Model suppressor [Allen Engineering AEM5 and brake/collar]
• Scope Rings: A.R.M.S. #22 Medium rings on PRi recce rail (rings should not include "lever-stop" hump as produced later by A.R.M.S.) or LaRue LT-104 SPR mount
• Optic: Leupold 3-9x36mm TS-30, Mk4 MR/T 2.5-8x36mm TS-30A2, M2 turrets with Mk262 BDC, illuminated TMR reticle, Leupold Vari-X III 3.5-10x40mm LR, M3 turrets, illuminated Mil-Dot reticle (use .308 turret) [Leupold LR/T 3.5-10x40mm LR, M3 turrets, illuminated Mil-Dot reticle]; S&B Short-Dot
• Bipod: Harris with either A.R.M.S. #32 or KAC RAS bipod adapter
• Iron sights: (apparently PRI were supplied but never used)
  
  

In the Wild
Naturally, once these rifles were issued to units, operators and even Marines used various non-issued parts. Here is a short summary of what has been seen:

Early SPR/Mod0:
Both Leupold 3.5-10x40mm and 3-9x36mm scopes have been used. Many have had carbine stocks like the old CAR-style, enhanced M4, SOPMOD Gen I, or even the Tactical DuoStock swapped on.

Mod1:
One 3rd SFG-issued rifle pictured with SSgt Robert J. Miller (MoH recipient) used an A.R.M.S #36 S-EX 5.56mm rail, and a Leupold M3X 10x fixed-power scope, possibly pulled from an M-24 or SR-25 rifle. Another has been seen with a Magpul PRS, LaRue mount, and a Premier Reticles 3-15x used by an AMU shooter, and a similar rifle was pictured on a FOB in a very posed-looking photo. Further, a USMC-issued Mod1 was seen using #22 Medium rings instead of High rings, and a LaRue mount has been spotted as well. Grips have varied from the usual A1, A2, and ERGO, and at least one Magpul MIAD has been used. As with the Mod0s, carbine stocks like the SOPMOD and M4 have been used on Mod1s.

ModH:
The Mod "Holland" was already a small-batch configuration, but even as soon as they were issued to 5th SFG units, some Ace SOCOM stocks were replaced with Magpul ACS and CTR stocks. Optics are basically anything existing in the unit's inventory, from S&B ShortDots still in the system, the 3-9x and 3.5-10x Leupold scopes from earlier Mod0s, and there's even a photo of an ELCAN on a Mod1 floating around. No non-magnified optics like EOTechs or regular Aimpoint M2/M4s, but Micros have been seen on offset mounts. Backup iron sights, as a whole, were almost entirely left unmounted. Grips were again the same usual selection.

Parts Alternatives for Clone Building
Many parts are rare, expensive, and/or both. Despite this, there are some alternatives to a 100% pure clone that will still provide the same visual look and performance. While not a museum-grade clone, most would be hard-pressed to discern the difference. Just know there are those of us out there that will haze and peer-pressure you into further moving your build towards a true clone.

Barrel:
Popular options are the White Oak Armament SPR barrel (rifle gas), BCM's SPR barrel, Rainier's Match and Ultramatch offerings (ensure it's the SPR contour with 12th Model profile), Ballistic Advantage's SPR barrel. Compass Lake Engineering can also spin a Mk12 profiled barrel with a Criterion chrome-lined blank, or even a Krieger, which was one of the original contenders for the program. The DPMS Mk12 barrels are NOT properly profiled for a clone.

Optics & Rings:
In the case of the Leupold 3-9x or 3.5-10x, it's generally okay to go for a non-illuminated version of either, sometimes with M1 or other turrets and reticles. As far as the NightForce scope, the 2.5-10x24mm is not generally released to the public anymore (with one recent exception through Sniper's Hide), so many use the 32mm or even 42mm versions with the #22 High rings. As for the rings, any of the recent produced A.R.M.S. #22s with the lever-stop humps are functionally the same, the desire for non-lever-stops is purely aesthetic when going for the most authentic look. As LaRue LT-104s have been seen in use, it is justifiable to use one depending on whether you have a specific rifle you want to copy, or even just if you absolutely cannot acquire #22 High rings.

A.R.M.S. #38 SWAN Sleeve:
The #38 family of sleeves are no longer available. Finding them secondhand usually cost $250-$300 easy, more for rarer early variants. Fortunately, PRi's copies of the sleeves look and function almost identically, with minor visual differences. PRi and other builders supply these currently for complete Mod0 builds.

FSB:
While the set-screw version of PRi's FSB is spec, most use the cross-bolt, clamp-style version. They are extremely robust, and when aligned and torqued, have been shown to hold strong enough that you'll probably shear your barrel extension pin or upper before it budges. This is mainly how Mod0 uppers are supplied by most vendors, including PRi themselves.

Suppressor, Brake/Collar:
Diverging from the OPS Inc. or AEM brake and collar will get you MAJOR flak. Trust me, I've been running an AAC SPR/M4 for years now and it took a LONG time to not get clubbed every time I posted it. The Allen Engineering AEM5 is basically the current production of the OPS Inc. 12th Model, as they were originally made by Ron Allen and his team in the first place. Only minor differences separate original OPS Inc. cans from AE cans, and these are only obvious to trained eyes.

As far as the rest, you can swap Colt parts out for any other .mil-spec parts, like BCM, DD, CMT, etc. Any billet uppers/lowers, funky BCG coatings, extended bolt releases, etc. are extremely frowned upon. Remember, once you start going down the path of building a "better" rifle rather than what was spec, you're quickly beyond clone territory and would have been better off building a custom 16" or 20" rifle. Cloning is generally viewed as all-in or not at all.

* * * * * * * * * *

Complete Mk12 Mod0 / Mod1 Uppers
Bravo Company Manufacturing
High Caliber Sales
Precision Reflex Inc.

Specific Mk12 Tech
Augee's side-by-side comparison of the original ARMS SWAN Sleeve and PRI reproduction PEQ Sleeves: bottom of p136
KOBK's side-by-side comparison of PRI Gen I, II, and III handguards, and Gen I and Gen II FSBs, and SWANs: middle of p137
Augee's Mod1 gas block tech: top half of p357
Glass1's Early Mod0 photo breakdown: middle of p449
tamboi's Leupold Vari-X, TS30, and TS30A2 scope history/lineage, and part numbers, p.792

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I think with these items we should have everything that goes in the cases. I don't know of anything else missing.

That is gorgeous, thank you!

Thanks man.  Ordered yesterday and still have to ship one barrel back to BA for that thread issue i had.  Looks like ill have an extra barrel that will probably mutate into a mod 0.

You gotta start somewhere.

If I had a dollar for every rifle that started because I had an extra mag catch laying around....

Damn, those are sexy. Can't wait to pay for mine!

Thanks again for doing these.
What is pretty neat about this group as a whole is that when there is a need for something, some figures out a solution to the problem.
On that note, a package came today from a pretty good guy.  Hopefully a couple more will start to show up here too.

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Real one for reference :

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Right? The fact that I can think of a custom receiver end plate, and probably find someone on here to make it for me, is awesome. Makes me think anyone is possible.

I'm not a mod 0 guy, but those look flawless. Post a picture of it mounted up, when you can. That looks great.

Cheers! I had to order one. Now begins the slow Mod 1 build process.

Mod 0 progress

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So awesome. 

@mrsaturn7085


Have you cross posted in chenault's Official Mod-H (Holland) thread?

http://www.ar15.com/forums/t_3_118/703269_Official-Mod-H--Holland--Picture-and-Discussion-Thread.html&page=1

You should, I would like to have some discussion on this to figure it out.

 

lol, you never disappoint blue

I believe that is incorrect information given by another well meaning company rep that probably was not around when the stocks were actually used. It seems to me that there has been a huge amount of discussion by people who would know and carried the mod h that we have it correct. I have 4-5 different ace stocks. I have gen 1 stocks that even have a different style sling loop. One has a weaker looking swivel then it looks like they beefed it up. The gen 2 I have has the collar you can flip from right to left. More of a long slot and not a sling swivel which would make sense to be gen 2 because it goes to a much easier way to have an ambi attachment point. Going from the slot collar to the sling loop just doesn't make sense to me. Then the gen 3-4 we don't care about anyway. I only have the original box and paperwork on a gen 1 I believe. I will see if there is a date on it. Also did doublestar always own the ace stock or was it owned by another company in the beginning? I've been given false information more than once by a well meaning rep. Augee usually straighten these things out. I also know someone else I may be able to ask. I'll email him. Does anyone have some in the wild pics that may show this? I will also say the gen 2 I have with the slotted collar is pretty hard to find. The one I have is the only one I've seen and I bought it by accident thinking it was a gen 1.

ACE ltd. made them originally. then doublestar aquired them at some point. im guessing about gen 3 timeframe. mary at DS has given us false reports on stuff as well as the guy in ordering/inventory. after we sought out gen 1 and gen 1 parts 6 months ago and were told they were gone after a thorough sweep of inventory, a BUNCH of long gen 1s surfaced on gunbroker (remember them and how weird it was they all popped up bnib? thabk us LOL).....and the contact for them? MARY. yep. a cloner bought a long gen 1 off gb and i made it into a carbine gen 1. he bought it from mary and sent it to me. no lie. so whatever ds tells me about a stock they didnt make and whats on hand, is bullspit. :). we have a running joke that when something doesnt exist but pops up out of nowhere, they "musta talked to that ***** mary" LOL

@chenault: it was either that or the "you are fake new"s one LMAO. 

So nothing too major to update. After my last range trip a couple weeks ago I ordered some parts to correct a couple issues. My ejection pattern has been consistently at 1 to 2 o'clock and when I got home and did a quick wipe down I noticed that in the process of staking my end plate I got to close to the edge and cracked it so excuse to spend money. I ordered up a colt 4 position receiver extension and a colt H2 buffer. The RE was bc I needed the right one and since I was going to be replacing the end plate I figured now is the time. I also found a couple colt 20's and I need to grab a new end plate and the lower can go back together. On another note I know that predator mount isn't kosher but it's the tits! I got to don some transitions with it and it is clutch in that position.

I think Samson and blue have said everything I would say with the exception of the gen 1 tube slots are crappy and wear really fast; I can't see them going from a superior design to an inferior one later on, it doesn't pass the common sense test.  We're correct on the gens of the ace stocks but I think these discussions are good to reeducate newer members.

Chenault out

Happy Easter y'all.

And yes I know my glass isn't kosher lol. Working on it.

Happy Easter, terrific post!  BRAVO

Any help finding some glass would be appreciated. 100% clone correctness only. Mod h

That's all I'm lacking.

DoubleStar did acquire the ACE line at some point.  Tim at DoubleStar took a few days to research this before giving me this information.  He also asked for a link to this thread to clear up misinformation, should it pop up in the future.

I ordered a replacement Gen 2/3 carbine length stock p/n A613 and got a stock with a square button indent.  This was enough proof for me that the Gen 2/3 stock had the square button...

Frankly, I could care less if anyone here believes this.  The round and square button stocks are both correct given the images shown here (round button stock shown with a lathe in the background, below), and this covers Gen 1-3.  The round button stock has two grooves on the top and all other tubes have one - in terms of product development, it makes the most sense that you wouldn't start with 1 groove, go to 2, then back to 1...

Feel free to give him the mod h link if you want.  I think all anyone wants are the facts.  Reguardless thanks for posting

I am contemplating a build and have a desire for more punch. Have there been any MK12 variants fielded in 6.8spc?

There were prototypes made, but never issued. The prototypes used different parts than any of the issued Mk12s.  Can build any of the issued Mk12s in 6.8 and pass muster for appearance.

Happy Easter

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so what I have found is the 3 items together were $44 and some change when broken down. so basically the bore guide, ballistic card and a round count log is $45. shipping from texas to Georgia was $10 shipped priority. understand some will pay a little more than actual shipping but some will also pay less than actual shipping just because its impossible to do anything besides average the shipping costs. box,bubble wrap, tape and plastic bag to put the round count log in about $4-$5 per set. i figured  $60.00 per unit. you get 1-black anodized bore guide, i heavy laminated black hills ballistic card and 1-round count log. shipped priority. I'm a little disappointed the packing and shipping jacked the price up like it did. shipping regular non-priority was only 30 cents less. i am not making a dime off these. actually with the manuals and this project i end up putting money in on things. which is totally fine. all these things are for the guys in this thread period and i enjoy doing it. i have the following people down for these. i believe if everyone on the list gets theirs i will have maybe 8-10 extra for late comers. i can not do another run of the bore guides. i bought all the guy had. i do have some extra round count log books. if somebody wants a couple extra i can include them for $4.00 each extra until they are gone. please EMAIL EMAIL EMAIL me if i missed you or any other comms. [email protected]. please contact me if you asked for multiples so i can account for them.

also please everybody speak up if you have ideas to ship these any cheaper. i just didn't want to risk damage to anything since it cant be replaced.i also want to thank the people that helped out on some of the things i needed like the round count log. you know who you are. that being said i think everything came out great and everybody should really like them.

KavonTN
Mad4wd
Sommer54
DSLMGK
_B_
PRaddict
Gunnut003-5
Blbennett1288
engineer5
armedferet
CJWD2
Dobs13
KOBK
aaron580
emc9001
hairymoose
unstable
johnnymoses
ichiban11
NHM16
Vanquishings
stampcollector
bbuenme
djc106
stxdobie
haveblue83
prskiller
tinman44
ironbalaclava
ejc204
minuteman1636
t_stone
daojag
lonewolfgun-3
oldtusko
lancecriminal
coilcrafter
frbaseball-round count logs only?
tahoelt

Your efforts here are much appreciated. shooting you an email regarding grabbing a few extra round count logs on my order. I, for one, will be throwing a few bucks extra on top just for the effort you put in on these. I hope others join me with a similar gratitude.

Off topic. I am looking for a picture of a KAC URX3 with a KAC vertical grip directly attached.There was additional information that followed. I believe it was in this thread. Can anyone direct me to it. Thank you. Richard

+1 on all fronts.

Email sent.

Yesterday, I made a couple changes to my Mk12 Mod 0 that I built several years ago. I swapped out the stock and the pistol grip with an original E type stock and A1 pistol grip.

Before:

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After:

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I know some prefer the SOPMOD but I like the look of the A1 stock on the mod 0 or mod 1. Functionality depends on the user I guess.

I know....I like the sopmod but the A1 just looks right. I am contemplating switching back now after that.

To me, an A1 sucks on the mod 1 because of eye relief.

If anyone gets a good lead on a 3.5-10 for a mod 0, please give me a heads up.

Plus the rifle length buffer shoots as soft as a .22lr when running a suppressor

Dude I'm looking for a 3.5-10 also. Non-illuminated. I get your point on the A1. I've heard people say that. I think it depends on your physical build but as far as the look of the gun the A1 wins.

Here are two pictures I believe to be issued guns that inspired me to build a mod H. They clearly have square release buttons and sling swivels. If these are not issued guns then my mistake. Please find some pics of issued guns with the socom stock your saying is gen 1. Its hard to find any pictures of the socom stocks because from what I understand they were removed almost immediately once the rifles got to the units.
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Which scope is that on the bottom?

There's a few still in stock at places for sub $1k for the non-illuminated.

Edit - Can't remember if they're TMR or mildot off the top of my head.

Samson I have sent an email regarding an order for the log books and bore guide. Thank you.

Here is another issued rifle. This picture was sent to me courtesy of Augee. He backs up everything we have been saying and verified the description and photo in the mod H thread is indeed correct. To the best of his knowledge. I've never asked what he does. I've asked a lot of questions of him and he knows his shit. Again if you have any proof as in pictures of a different ace socom on an issued mod H please share. That would make a couple of my stocks more valuable so I'm all for it.
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Samson-Dogg, I have all of those photos.  Yes, the square latch is correct... I get that, it's what I have on my rifle.  The point I'm trying to make is that when you go to order spare parts for what I'm calling a Gen 1 (round latch), they aren't available.  Gen 2/3 parts are, however, and when ordered, they are the square latch parts.

Yup,
Samson-Dogg's contribution to this forum is above and beyond. I'll be throwing him a couple bucks more as well for his efforts.

Email sent!

BTW fellas,

Was a Kill Flash issued with the Leupold MK4 MR/T and LR/T optics in the Mod 0/1 package?

That makes more sense. Would you mind posting a picture of your stock and what parts you ordered and explaining all that. If you don't mind. I know I along with others need spare parts if they are available and it would help to get the right pieces when ordering. Either here or the H thread.

I've seen some with the tenebrex kill flash. There were a few M24 tenebrex filters floating around but I don't think they were actually issued. They look cool though.

Yeah,
Always wondered about that. Anybody have any ITW pics of MK12s with a Killflash installed?

Do all mk12 variations run the 8.5" rail on the bottom or just the H?

I've seen the gen 3 run them

Most of the late mod 0's w/ the gen 3 tube run the 8.5" bottom rail. I don't remember if I have seen a late mod 0 with a short rail on the bottom. I think the early mod 0's run the short bottom rails.

Which scope is this?