It's a nice ir illuminator - Armasight XLR-IR850 Detachable X-Long Range Infrared Illuminator

I'll start with the negative side to this IR... When it's at its most tightly focused position you will see artifacts in the beam. That's all that I have found wrong with it thus far.

It solid. It's focusable. It has adjustable brightness settings. On high and tightly focused it's useful to about 300 yards on my digital NV. It's smaller than most of the lesser cost ones on the market but with the same or better output. Run time on the 2 CR123s or 1 18650 is great. I haven't yet ran it down after hours of hunting. The best part is the tail switch. It rotates and has 6 click to positions with stops... OFF, low, medium, high, turbo, OFF. So just turn the switch all the way one direction or the other and you know that it's turned off without having to look through the NV or check the frontal glow to tell. Red glow is minimal for it's available light output. Includes the picatinny mount and mine also included an adapter to rimfire dovetail.