The Laser 3Dot is described as:
Uses three laser for fast target acquisition.
You’ll find this in northern Flor de Oro province, in a Unidad combat outpost. The accessory case is outside, next to the armoury on some crates behind a chain link fence.
There are only maybe a dozen or so Unidad soldiers at this base and this was one of the most enjoyable approaches I experienced. I began with some sync shots to take out the two snipers in the towers and a guy outside the wall near the road. You’ll see from the drone that there’s a nice open way into the base on its eastern edge by the road.
The base is split into two levels, and you can easily creep around the perimeter, taking down enemies as they break off and isolate themselves. There’s also a power generator on the eastern side which you can turn off easily should you wish, but with no alarm it’s not really necessary unless you approach this base at night. If things go wrong, you’ll probably attract some passing rebels who will pile in and help out anyway, so you should be fine.
The three lasers are meant to improve accuracy, but I do find them slightly distracting. I guess it makes you look a bit like the Predator though, which could be cool.
I usually prefer not to equip anything on the rail of my sniper rifles, so I don’t use this. It’s one of those accessories I can’t really tell if it does anything, but I imagine it would be more use on a semi-auto sniper rifle than a bolt action because with long rechamber times, you have plenty of time to get back on target after the recoil of a bolt action shot anyway.