K-SPEC: Mil-Spec, Enhanced. PHOSPHATE COATED & CHROME LINED OR FULL CHROME BOLT CARRIER GROUP KAK Industry's signature design for unrivaled performance and unparalleled reliability, all K-SPEC Enhanced BCGs retain mil-spec dimensions with added Slotted Angle Carrier Rails ("sand cutters") and Dual Ejector system. This 5.56 NATO model features KAK Industry's proprietary Down Vent configuration, venting gas downward instead of out at the shooter's face. This redirected gas system means a quieter, less gassy shooting experience. All KAK Industry BCGs feature a M16 (Full Auto) carrier profile, meticulously machined from 8620 steel, properly Mfg: Kak Industry Llc.