TROY Industries Battle Rail, SOCC151, 15.125 Rail, Fits AR, 5.56, M-LOK, Aluminum, Black Finish SRAI-SR1-15BT-00 Troy's SOCC BattleRails with M-LOK cooling holes are narrow" sleek and provide exceptional balance and controllability. Lightweight with an ultra-low profile" snag-free design" they are ideal for close quarters maneuverability. Machined from hardened aircraft aluminum with stainless steel components and finished in Mil-Spec hardcoat anodizing" they mount to a standard barrel nut.