Premium Roller Timing Chains feature the highest quality chains. Milodon timing chains have huge .250 inch diameter non-split design rollers that actually roll into the sprocket, reducing power-robbing drag. Unlike most other timing chain sets, the Milodon chain almost eliminates chain stretch problems even in racing conditions. Cam and crank gears are CNC machined from high tensile strength, heat-treated material. Both timing chain gears use a wider tooth profile for superior strength and wear resistance.