The Resonator(R) K blast chamber is threaded to the popular 1-3/8"-24 HUB thread to accept many mounting options. The suppressor can also be used with rifle calibers ranging from .17 HMR through 300 RUM. The Resonator(R) K uses a shorter but similar tubeless design which consists of heat-treated 17-4 stainless steel and a heat treated Cobalt 6 blast baffle which allows the suppressor to be full auto-rated and designed for rigorous use. It comes Phantom(R) Q.D. Adapter (YHM-3060), Phantom Muzzle Brake (YHM-4302-MB-24A) and two suppressor wrenches. Tech Specs: Weight: 9.6 oz./12.4 w/Q.D. adapter Length: 4.8"/5.65" w/Q.D. adapter Diameter: 1.562" Caliber: .30 Construction: 17-4 PH SS/Cobalt 6 Blast Baffle Mount: Phantom(R) Q.D. HUB adapter with 5/8\" - 24 threads Decibel Rating: 137 dB Minimum Barrel Lengths: 7.62x51 / .308 Winchester: 10.5" 5.56 NATO, 6.8 SPC, 7.62x39mm: 10" .300 Win Mag / 300 RUM: 20" 300 Blackout: 7.5" Full Auto Rated Made in USA