AIM VP68 IV Easy pull performance clutch spring for '98+ modelsVP68 IV is a easy pull model recommended for light performance engines producing 100 145ft lb of torque! (Dependent on diaphragm pressure rate. See chart here) For Harley Davidson '98 to '17 Big Twin models with 6 Studs Style Clutch and Diaphragm Spring. (except '13 and later Big Twin Model with A&S Clutch, 3 Studs Style) Click here for the fitment chart. 40% Reduction in clutch pull effort. 15 minute installation. Install through the derby cover