The SRD22 22LR Silencer can be used on both pistols and rifles and features an aluminum outer tube with 17-4 stainless steel baffles. Due to the durability of its materials the SRD22 can be used with .22LR pistols and rifles chambered in .17HMR/.17 Mach II and .22 Magnum. The SRD22 comes with both 1/2x 28tpi M9x.75 rear mounts and is fully user-serviceable. – CALIBER: 22 LR / 17 HMR / 22 Win Mag – WEIGHT: 7.7 oz (218 g) – DIAMETER: 1.25 in (32 mm) – OVERALL LENGTH: 6.25 in (159 mm) – THREADS: 1/2 in – 28 & M9 x .75 mm – ATTACHMENT TYPE: Direct Thread – MATERIAL: Aluminum / Stainless Steel