Side mounted process using an integrated MILSTD 1913 rail piece for sighting devices. Designed for use with the M203. just one info place, I picked up two or three salty utilised P&S M4 RAS's from Thoroughbred for $one hundred fifty ea. yeah, not KAC, but good enough for me. This https://beauhtepy.blogscribble.com/29581721/rumored-buzz-on-kac-drop-in-rail