This Airsoft Gun is based on the AR/M4 platform and is another in G&Gs insanely popular Combat Machine series, which are famous for their longevity and user friendly design. This variant of the Combat Machine offers an 13" KeyMod rail system which is built from Alloy and Powder Coated to promote better grip.This Rail System saves on weight by being a less bulky design and allows you to install 20mm adapters or use KeyMod compatible accessories directly onto the rail.