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