ENGAGE AR15/M16 Pistol Grip, BlackFeatures:- Designed for M16/M4/AR15/HK416- Covers the receiver gaps that cause discomfort during sustained usage- Finger swells and a grooved back strap provide a non-slip grip- Secure watertight storage compartment- Plug retention for one handed storage access- Customizable foam storage block with quick access tab diminishes rattle