(SOT required for purchase. Silencers may not be combined with other product when shipping.) - Size: 5.56 NATO - Sound: 134 dB - Material: Inconel 718 - Size: 6.5 x 1.625 - Weight: 14 oz - Threads: 1/2-28 tpi - The SRD556-QD is an Inconel 718 silencer using fast-attach muzzle devices to mount the silencer to the rifle. Inconel 718 a Nickel Alloy Stainless Steel provides the highest level of durability particularly with short-barreled hosts using supersonic ammunition. The 5.56mm fast-attach muzzle device system is available in 1/2x 28tpi threads matching the vast majority of modern sporting rifles in .223/5.56mm on the market today. The rear mount has wrench flats to torque the silencer to the barrel. There is a secondary retention latch that is depressed to remove the silencer from the fast-attach mount. The SRD556-QD comes with one 1/2x 28tpi Taper-Lok muzzle brake.