Built with the legendary and unique MREX profile, originally designed for the FN SCAR, the AR-MREX offers unmatched performance. The AR-MREX profile utilizes a flat base for a comfortable grip, easy weapon manipulation and a stable shooting platform when engaging from barricades, bags and rests. Lightweight, extremely durable, and very well vented to exceed the demands of any shooter. Whether at the range or down range, at home or on patrol, Gain the Advantage with the AR-MREX. SPECS Finish: Black Anodized – Type 3 Hardcoat Material: 6061 T6 aircraft grade aluminum Compatibility: AR-15 style upper receivers 9.5” RAIL Length: 9.5 in Rail Weight: 7.5 oz Overall weight: 9.8 oz 11.5” RAIL Length: 11.5 in Rail Weight: 9 oz Overall weight: 11.3 oz 13.5” RAIL Length: 13.5 in Rail Weight: 9.9 oz Overall weight: 12.2 oz"