Pro Series AR15 Barrel Wrench - heavy duty purpose built barrel wrench Large heavy duty cross section makes it easier on the hands to work on your AR upper. You can remove/install GI barrel nuts with ease with this AR wrench. Makes for assembling/installing barrels and free float handguards a super easy task. The other end of the wrench is for installing/removing 5/8" muzzle brakes and flash suppressors. 1/2" and 3/8" drive compatible, for torquing your barrel nuts to the proper torque specifications.