The BCM M-LOK Compatible Modular Rail (MCMR) delivers the same optimized ergonomic profile and lock up developed for the KMR-Alpha rail system, but with an M-LOK compatible interface, precision machined aerospace 6061-T6 aluminum alloy, the MCMR is both rigid and light-weight, featuring mounting interfaces on seven sides in addition to the baked in MIL-STD-1913 at the 12 o'clock position.Features: MCMR features M-LOK compatible mounting systemFree float handguard eliminates loads from barrel, reducing the deflection for more accurate shootingPrecision machined aerospace 6061-T6 aluminum alloy, for high strength and lightweightProprietary engineered profile offers additional cross sectional strengthSteel barrel nut (same KMR, MCMR and QRF series), to resist movement under heatHard coat anodized per Mil-A-8625F, Type III, Class 2Handguard alone weighs 9.2 ozHandguard mounting hardware 2.3 oz