Lancer's Viper Brake is a ""tunable"" brake designed for precision shooters. It's engineered with a blast chamber and four tunable jets to effectively reduce recoil"" making for faster follow on shots. Different sized jets are supplied so the operator can tune the downward force. Angled blast baffles reduce recoil"" further stabilizing the rifle. Made from stainless steel for .30 and 6.5 caliber rifles utilizing a 5/8-24 thread pitch. Includes a jam nut and six tuning jets.