Nuke Performance adjustable cam pulleys allow for fine tuning adjustment to cam timing to maximize performance. Adjustments can be made to tune an engine’s power band to an optimum RPM range for different applications. The pulley is CNC-machined from 6082 aluminum alloy and hard anodized for long life. Three M6 bolts are fastened with helicoil inserts for long durability. There are also hard washers included to make sure the pulley can do it's job on the racetrack or in a drag race and you don't lose your tune settings even under hard pressure. Tightening torque is 17 NM. For use on BMW M20 engine.