Side mounted system using an integrated MILSTD 1913 rail piece for sighting programs. Made for use Using the M203. only one details point, I picked up a couple of salty used P&S M4 RAS's from Thoroughbred for $a hundred and fifty ea. yeah, not KAC, but ok for me. They https://elliottlyhsb.dm-blog.com/29606134/little-known-facts-about-knights-armament-m4-quad-rail