Features: LWRCI(TM) 20-Position Tunable Gas Block Patented LWRCI(TM) short-stroke gas piston system offers unparalleled reliability and easy maintenance Monoforge(TM) upper receiver with integrated rail-base is stronger than the standard-pattern upper Carbon Fiber Wrapped 1:8 RH Twist PROOF Research's match-grade carbon fiber barrels are stronger lighter as accurate as the finest precision steel barrels and will maintain their performance in the harshest conditions