Geissele Premium MIL-SPEC AR-15/M4 Black Buffer Tube Assembly 08-163B-H2 pairs Geissele's mil-spec buffer tube with the Super 42 Braided Wire Spring and Buffer Combo, improving function and reliability on an AR-15 carbine build. The buffer tube is machined from 7075-T6 aluminum and finished in Type III hardcoat anodize, conforming to all mil-spec standards with 6 stock positions. This carbine-length, mil-spec diameter tube weighs 3.7 oz and is made in the USA, ensuring compatibility with most mil-spec diameter quality AR-15 stocks. A high-quality mil-spec castle nut and end plate come included in the package. The Super 42 spring uses three independent strands of wire, the same design used by the German MG42 machine gun. That braided design operates like a harmonic damper and energy absorber, letting the strands flex independently from each other. This displaces energy and decreases the risk of spring failure while making the rifle more reliable. Compared to a standard spring, it's less likely to lose length and force over time and eliminates the spring reverberations felt through the buttstock. Its return force runs roughly 15% stronger than a standard spring, which helps strip cartridges from the magazine when the weapon is dirty or running steel case ammunition. Key Features: Buffer tube machined from 7075-T6 aluminum Type III hardcoat anodize finish 6 stock positions, mil-spec diameter and length Weight: 3.7 oz Includes mil-spec castle nut and end plate Super 42 Braided Wire Spring, three-strand design 15% stronger return force than standard spring H2 buffer weight included These Geissele parts replace two of the weakest links in a standard AR-15 buffer system with components built to outperform them. Geissele Premium MIL-SPEC AR-15/M4 Black Buffer Tube Assembly w/Super 42 Combo H2 08-163B-H2