Fab Defense GL-Shok AR-15/M4/M16 Stock - Black - The revolutionary patented GL-Shock absorbing Buttstock contains an "Anti-Rattle" recoil-reducing mechanism with a built in premium silicon chrome alloy spring creating a State-of-the-Art stock for your AR-15/M4/M16. Made from Mill-Spec reinforced polymer composite, the stock is compatible with both Mil-Spec and commercial tubes and has watertight battery storage for two CR123A 3V lithium batteries or AA 1.5v. It features an integral ribbed rubber butt pad with a non-slip design and Quick Detach sling swivel connectors on both sides. This model has a black finish. Features Unique Patented "Anti-Rattle" Mechanism; Sleek New Design with No Protruding Parts,Will Not Get Caught on Gear and Webbing; Unique New Slick and Quick Operated Inversed Positioning Lever; Integral Ribbed Rubber Butt Pad with a Non Slip Design; Integrated Quick Detach Sling Swivel Connectors on Both Sides; Watertight Battery Storage for Two CR123A 3V Lithium Batteries / AA 1.5v; Fits Perfectly on Both Tubes - MIL-SPEC and Commercial Aftermarket; Made from Mill-Spec Reinforced Polymer Composite;