Convert your HUB-equipped silencer to accept P-Series adapters. This is the same accessory included with the Primal, which is designed to handle most rifle and pistol calibers. Always ensure your suppressor is compatible with the caliber you are shooting. Outside Threads are 1.375-24 for (HUB) silencers and inside threads are 1.125-28 for (P-series) accessories such as booster, 3-Lug, Keymicro, and P-series Fixed mounts. SPECIFICATIONS: Overall Length - 0.545a ^2 Weight - 0.88 Oz Material - 4140 HT Alloy Steel Finish - QPQ Black Nitride Mfg: Dead Air Armament