Muzzle Device Alignment Set Includes: 1x Large Shim 6x Medium Shims This shim kit is a replacement for the peel washer and is used for mounting muzzle devices. New muzzle brakes are normally supplied with the necessary washers, nuts, or shims; however, sometimes replacement washers are needed if one is damaged or if installing a muzzle device on a different gun. While Peel washers require you to heat them and then peel off separate layers of the washer to get to the desired thickness, a Shim Kit is much simpler. There is no heating or peeling of layers needed. Just install the necessary combination of shims to get the precise alignment you need. Each shim set ships with QTY 1 of Shim 1 (largest), 6 (Medium). The large shim can be used to give the installer one half of a rotation or as a spacer for barrels that do not have relief cuts behind the threads. Shim 2 is used in varying quantities to achieve the proper alignment of your muzzle device. This shim gives the installer approximately 45 degrees of rotation. If needed, Shim 3 can be used where smaller degrees of rotation are needed for proper alignment.