An engine’s camshafts must be set at their proper positions relative to the crankshaft in order to maximize horsepower. The Pro Series Cam Gear for Honda's D15/ D16 SOHC engines enables serious tuners to optimize horsepower and torque by being able to adjust camshaft timing +/- 10 degrees, allowing them to tailor the power curve appropriately. Thanks to laser-etched timing and directional marks, precise camshaft adjustments can be made quickly and easily. Pro Series Cam Gears feature precision-machined, hard-anodized teeth to reduce premature wear with a signature, six-bolt design that eliminates gear slipping. Skunk2’s lightweight design (35 percent lighter than OEM) and CNC-machined, 7075-T6 billet aluminum construction reduces rotational inertia, resulting in increased engine response and acceleration. Skunk2’s adjustable cam gears have also been proven on race cars in the most extreme conditions for more than a decade.Gear does not include a woodruff key, you will need to supply a B-Series woodruff key from a local Honda Dealership.OEM Part # 90741-657-000