This Shim Kit for barrels with 1/2-28 threads is composed of three different shim thicknesses. The graphic on the packaging details the thicknesses and identifying features of the shims included with the kit. Always place the thickest shim(s) on the barrel first. One notch – Qty 4, .004? thick, ~40 degree rotation, ~1/9 turnTwo notches – Qty 5, .006? thick, ~60 degree rotation, ~1/6 turnNo notch – Qty 1, .060? thick, ~1.7 turn Dead Air Silencers Dead Air Muzzle Device Shim Kit 5.56 DA001