So I shared this with one person a while ago but decided it was a cool little idea that any vintage Surefire guys would dig.
You can connect modern Surefire tape switches to your old 6 series light. Here you go.
*I did not come up with this mod. This was shared to me by a friend.
Start with the UM00 Tailcap from a millenium light
Next, grab your standard 6p tailcap and gut it. (if you do not know how to gut it I can post a diy on here, it is pretty easy but requires you to use any oven on like 200f for 10 min).
Next, you pop the insert out of the UM tailcap. It is annoying because the little dust cap has to squeeze through with the unit but no more than 20 seconds of work.
And the final piece. Insert the UM unit into the 6p tailcap. Boom. My super secret mod.
It works 100% perfectly and seals perfectly. Now you do not have to use the junk 660 tailcaps with the built in switch.
Dual pad? No problem
Also, you may be wondering why run a shitty incan light? They all have Malkoff M61 drop in heads. So they are 450lm potted led heads. Never had one die yet.