This aftermarket 1911 Vice block tool is for securing 1911 pistol slides onto a vice is specifically designed to fit most 1911 slides. The slide vice block makes it easier to work on and service the 1911 slide. A great way to secure the slide onto the vice jaws to remove and replace the front and rear sights on the 1911 pistol slide. Insert the slide vice block onto the frame rail grooves of the slide and mount onto the jaws of a vice. Gradually tighten the vice jaws onto the slide vice block, until the slide is secured making sure your do not to overtighten the vice jaw and you are read to work on your 1911 pistol. This vism vice block for 1911 pistol slides is made from Hard Anodized Blue aluminum.