The revolutionary patented 'GL-Shock' absorbing Buttstock contains a recoil-reducing mechanism with a built in premium silicon chrome alloy spring creating a State-of-the-Art stock for your M4/M16. Advantages:

• 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