Otis FG-ARLB Pro+ Ar-15 Lock Block - Upper Receiver Vise BlockOtis FG ARLB 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