Does the job - Primary Arms Classic 21mm Micro Reflex Sight

I put this on my Glock 43X MOS. The 43X requires an optic plate for some other optics, and I wanted to co-witness stock sights, so I chose this. I like the 3 moa dot size on these smaller window optics. The up/down buttons are in the right place, on opposite sides of the optic. The glass is clear, and the dot is nice as well. I do wish it had shake awake, but turning it off when not in use isn't too bad. The battery is under the optic, but it is a bigger 2032 battery, so it should last a year at least. One thing that I didn't like was that the included screws didn't fit the 43X.