I got these to put on my Bushmaster carbine. The front sight is easy to install. The rear is a little more work. It comes with instructions (although XS sights have a good You Tube video that is great) and the front sight adjustment tool.
I recommend getting the front and rear sight set. Although the rear dots are very blurry in low light, without them you have no reference for the aperture. There is no reason to get any color other than green for the rear. Since the rear dots are so blurry, there is no mistaking which sight is the front.
My only complaint is that the front sight silver outline could be wider, but it is still an improvement over the standard black post. I had no problem doing the "battlesight" zeroing today.
All 3 dots were very bright. It's not Aimpoint or EOTech, but it gives me sights that are low/no light capable with having to spend big bucks.
Pros: Value, dot brightness at night
Cons: White outline during daytime
This review was written in the old system and had content requirements that are different than reviews written today.