YANKEE HILL MACHINE RESONATOR R2 30 CALIBER RIFLE SUPPRESSOR YHM's .30 caliber sound suppressor, the ResonatorA(R) R2, can be used on rifle calibers ranging from .17 HMR through 300 RUM. Like the TurboA(R) T2, the ResonatorA(R) R2 uses a tubeless design which consists of heat treated 17-4 stainless steel and a heat treated 718 Inconel blast baffle which allows the suppressor to be full auto rated and designed for rigorous use. Includes YHM-4302 Q.D. Mount of your choice. Sound Pressure levels are as follows: 20" Remington 700 shooting .308 Winchester 147 grain measured 135Db 16" 6.8mm AR-15 shooting 110 grain mea Mfg: Yankee Hill Machine Co., Inc.