The revolutionary patented GL-Shock recoil 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 AR-15. Additional features include the ability to be used with either a Mil-Spec or Commercial diameter buffer tube, a non-slip rubber butt pad, water resistant battery storage compartment and (2) QD sling swivel socket points.