I know there are other laser devices that can be had, but what is so special about the OTAL?
I'm not bashing just wanting to know........
It's a solid & reliable little unit. I have had one for over a year, it has been mounted for thousands of rounds and still works perfectly, has never lost zero, couldn't be more satisfied.
From the Laser Devices website:
Complies with MIL-STD-810
Fits all NATO 1913 and Picatinney rails
No tools required
Offset design allows the laser to be mounted behind the front sight cage on AR-15, M-16 and M-4 style rifles
Operates using a single AA battery
Standard with a pressure pad switch and rotary ON/OFF switch
Windage and elevation adjustment knobs are protected from impact
Windage and elevation adjustments can be made in precise 0.4 milliradian clicks
Environment: Waterproof to 20 meters
Length: 2.8 in.; 7.2 cm
Limited Warranty: One year
Material: Anodized aircraft aluminum 6061T-6
Weight: 4.9 oz.; 138.9 grams with barttery
Width: 1.4 in.; 3.6 cm
Battery: One 1.5 volt AA
Battery Life: 5 hours continuous
Beam Diameter: 6.5 mm @ 25 meters
Laser Type: Laser Diode Class IIIa
Power Output: <5mW
Range/Visibility: 450 meters (low light) 30 meters daytime
Wavelength: 635nM (SPP)
To answer your question...
The thing that is "special" about the OTAL is that it can be mounted on the Top Rail behind the FSB and it shines it's light aorund the FSB. It is actually "Offset" from the bore line. Hence the name...Offset Tactical Aiming Laser (OTAL).
Another application is for use with Flip Up Front BUIS's. Your Laser will work with the front Sight in either the Up or Down position. i have learned the hard way that this is important if your laser is In Line with your Bore on the Top Rail. The laser shines very nicely on the back of the TROY Front BUIS.
The way I am getting around this is to get (as soon as they're available) the new LaRue 1" Offset QD Mount. I will mount it so my Laser is still on the Top Rail, but it will be Offset just like an OTAL for around $300 total. My LAS/TAC has a pressure pad that is mounted to my VFG as you would mount an OTAL Pressure Pad.
Hope this answers your question.