AEM Tru - Time Adjustable Camshaft Gears increase horsepower and torque without having to change the camshaft(s) and are must - have items for engines that are milled, forced induction, high compression andor utilizing aftermarket competition cams. AEM Tru - Time cam gears enable users to match cam timing with their vehicle's tuning state by advancing or retarding the cam profile(s) in one - degree increments via true laser - etched markings. Precision - cut gear teeth ensure no premature wearing of the cam gear's belt surface and AEM's anodizing on the adjustable cam gear's teeth is lab - test proven as the hardest anodizing process on the market.