F1 Racing Stage 3 Racing Clutch Kit F1-81024R3-SS 6-puck copper ceramic (also known as MIBA) disc features 12 high-coefficient friction pads that are resistant to slippage and ensures long lasting life Heavy-duty sprung center unit boasts heat treated springs and retainer rivets for the maximum power and durability Pressure plate features special single diaphragm design to increase clamp load. It features induction hardened diaphragm, CNC machined castings, stronger drive straps and rivets Provides smooth and precise feel with easy modulation Disc OD: 9-1/4", Spline: 10