Geissele Automatics 05278B Super Modular Rail MK4 Black Picatinny Rail Rifle
The Super Modular Rail (SMR) MK4 M-LOK are purpose-built and feature integrated M1913 picatinny rail sections at the fore of the rail in the 3, 6 and 9 o'clock positions. It also features Geissele's proprietary 2" long barrel nut.