IWI US, Inc Centerfire, Suppressor, 6MM, 1/2X28 HUB-T Mount, Black IWS6 The IWI IWS6 silencer features a 6mm diameter and offers a reduced back-pressure design for 5.56 NATO and 6mm rifles. Constructed with weapon-grade nickel alloy and stainless steel parts, and CNC laser-welded for durability, it handles the demands of short barrels and full-auto firearms while preserving the rifle's inherent accuracy.