BCM(R) Stock Assembly - Mod 1 - SOPMOD (Widebody) Compartment Strong and Lightweight for your mil-spec receiver extension. More pronounced cheekweld (SOPMOD type)Snag free Design. No sharp edges prevent tangling of the rifle with the shooter's sling, molle gear, or other kit.Modular VBOST (Vehicle Borne Operations Sling Tab) This tab interfaces with the shooter's riggers' band or bungee to secure the shooter's sling against the stock when the carbine is not in use. Increasingly, this is the most common application when operating inside a vehicle.2 different types of ambidextrous sling mounting options, including QD swivel sockets.Longer overall length to fit longer "MilSpec" diameter AR10/A5/Intermediate receiver extensions. Storage compartment located in the toe of the stock, accessible through butt pad.Two different ambidextrous sling mounting options.Built in rubber butt pad for secure shoulder placement. United States Patent Number: 9,109,855