The Otis Technology Pro+ AR-15 Lock Block is designed to make the removal and installation of barrels and even hand guards quicker, while also allowing you to tackle stuck barrel nuts with ease. Held in a standard bench vise, the AR-15 Lock Block locks into the barrel extension, securing it from twisting and minimizing the chance of marring. Give it all the elbow grease your project needs, the AR Lock Block has you covered. The torque is applied to the barrel extension rather than aluminum upper - for a stronger, more secure hold. To accommodate internal receiver differences present in the market, the AR-15 Lock Block is designed with a bronze bushing which allows the tool to work with slightly smaller internal specs. Designed for milspec receivers, the AR-15 Lock Block works on most ARs. Crafted from 1018 steel and finished in a manganese phosphate coating, it'll stand up to the job and then some. To use, simply lock the tool into a standard bench vise at your designate...