Short-stroke gas piston; Detachablereplaceable barrel; Simple field stripping into only 2 parts, easy to clean and no need for special tools; 20" barrel; 4 position gas regulator - Regular Extreme Suppressor Closed (for special operations); M-Lok fore end, provided MIL-STD 1913 accessory rails at the 3 and 9 o'clock positions; Covered MIL-STD 1913 accessory rail at the 6 o'clock position; 100% interchangeability, reducing the overall costs of the system; All the metal parts of the weapon are corrosion resistant; Body built of high strength impact modified polymer; Hammer-forged, chrome-lined, free-floating barrel, for enhanced accuracy and life cycle; Optimized ergonomic design; Pistol grips can be changed or modified; Fully Ambidextrous weapon; Non reciprocating charging handle