USED Ultradyne Mercury Compensator .625x24 6.5. 223 5.56 caliber to provide superior recoil reduction and neutralize muzzle rise with a smooth balanced release of blast energy. Progressive 90 side ports vent combusting gases at intervals that spread out the recoil impulse for efficient accurate follow-up shots. MERCURY is the choice for those seeking a compact lightweight muzzle device with smooth recoil characteristics and Dynamount on-barrel sight compatibility. A timing nut is included for easy installation. Specifications for Ultradyne Mercury Compensator: Manufacturer: Ultradyne Threads per Inch: 1/2x28 Color: Black Country of Origin: USA Features of Ultradyne Mercury Compensator Ultra smooth recoil reduction and minimal shooter distraction. 416 Stainless Steel with ultra-rugged salt bath nitride finish. Barrel-mounted sight option eliminates sight deflection associated with handguard mounting. Package Contents: Ultradyne Mercury Compensator Ultradyne UD10717: Mercury Compensator .625x24 6.5