Billet steel and aluminum clutch Offers twice as much friction surface area as stock Smooth, positive engagement and release for finding neutral and positive shifting Steel spacers on clutch pack ends assure no wear on aluminum surfaces 6 heavy duty springs instead of stock diaphragm Kit includes extra springs for tuning the clutch Easy tunability without removal of primary cover Compatible with any primary oil This product can be used with Model Part# Harley-Davidson Sportster 91-06 SCHD-1 Harley-Davidson Big Twin 90-97 SCHD-2 Harley-Davidson Big Twin (Except 06 Dyna) 98-06 SCHD-3