It is adjusted with allen screws. Each square, laser head sits on a rubber pad and has an allen screw at each corner. You adjust it with those screws.
It takes a bit to dial it in, but it holds fine when you get it there. I don't know how well it would hold up in combat though.
I have only mounted and used it once with my 6015 with live fire and it held zero fine. Since then I have not had an opportunity to use it; besides just playing in the back yard with the 6015.
Here is another unit I do use with live fire a lot though. It is also from SK Industries, and you can see how they adjust with the allen screws. It is only a visible laser unit, but it would be a blast in IR with a head-mounted NVD. It mounts in the end of the cocking tube on this AOW-registered SP89. The switch and battery unit are sealed inside the fore-grip.
http://i18.photobucket.com/albums/b109/Gewehr1/HPIM0299.jpgI am working on modifying the case so the laser can be activated from the briefcase handle...but who knows if it will work...
http://i18.photobucket.com/albums/b109/Gewehr1/HPIM0300.jpgThe IR units they sell are very nice though, and they are a good company to work with and have a lifetime warranty.
Just thought I would mention it, since choices in IR lasers are fairly limited.