The Centurion Arms patented CMR rail system is a lightweight, robust, free-float rail system for most airsoft AR-15 setups. Once installed, the CMR rail offers 13.5-inches of continuous 1913 mil-spec picatinny rail that feels like a completely monolithic (one piece) upper. The one-piece feel comes from the proprietary barrel nut that is included with the purchase of the rail system. As the name implies, the CMR M-LOK® features the Magpul M-LOK® mounting system, a modular rail system that decreases overall gun weight and increases customizability. The M-LOK® is utilized on the 3, 6, and 9 o’clock positions and runs down almost the entire length of the rail, allowing the user to attach a plethora of lights, grips, rail sections, and all other M-LOK® accessories. There are also four anti-rotation QD sling swivel sockets at the front and rear of the rail at the 3 and 9 o’clock positions to allow for the usage of a 2-point sling. Lastly, the Centurion Arms CMR M-LOK® rail utilizes the K.I.S.S. (keep it simple, stupid) design principle throughout the entire system.