FEATURES-Optimized for left hand or right hand Mil-Spec A2 upper receivers with carry handles or flattop style receivers-Safely clamps your AR-15 upper receiver without twisting, crushing, or marring the finish-Made of a high pressure, solvent resistant polymer material-Includes a receiver insert with a gas tube alignment system-Perfect for torqueing a barrel on, removing a stubborn barrel nut, or for simple gun maintenance & cleaning