HKS Adjustable Cam Gears allow fine tuning of the camshaft timing to maximize engine performance and tailor power characteristics for various driving conditions. Either with OEM or HKS Camshafts, adjustments can be made to tune an engine’s power band to the optimum RPM range for a particular application. HKS Cam Gears are made completely of anodized aluminum except for applications with timing chains which utilize an aluminum slide with steel teeth. Comes with both intake and exhaust gears.