This is a Tactical Solutions Compensator chambered in 22 LR, model 1022CMP-BLK.
The X-Ring 10/22(R) Compensators are a simple addition to spruce up any 1/2"x28 .22LR pistol or rifle. With 360 degree ports" Tactical Solutions compensators help reduce muzzle rise on your barrel.
Features:
1/2X28 thread pitch
Made for Ruger 10/23