Spikes Tactical Alignment Set 1/2in - Fake Cans & Muzzle Devices. This kit allows you to properly time your muzzle device so I will be positioned properly on your rifle for optimum performance. Large Shim is for _ rotation adjustment as well as for barrels with relief cuts. The medium shims each give you 45 degrees of rotation. The small shim provides even finer adjustments. Specifications for Spikes Tactical Muzzle Device Alignment Set: Manufacturer: Spikes Tactical Color: Silver Country of Origin: USA Features of Spikes Tactical Muzzle Device Alignment Set: Includes: 1- Large Shim. 8- Medium Shims. 1- Small Shim. Instruction Insert. Package Contents: Spikes Tactical Muzzle Device Alignment Set Spikes Tactical SAF0001: Alignment Set 1/2in - Fake Cans & Muzzle Devices