"Excellence in Performance", backed by the best one-year warranty in the industry! Sport/Race Rigid 4 Pad Light to moderate pedal effort, aggressive engagement, increased gear rattle; Moderate friction life, extended by ACT's exclusive diaphragm design, rigid design may increase spline wear; Carefully engineered, precisely assembled, accurately balanced, uses select ceramic friction materials for high heat tolerance and maximum performance; Recommended for race use only; 100% clamp load tested and dynamically computer balanced for smooth high RPM reliability MB1-SPR4 kit features a Sport pressure plate for a nice upgrade. ACT Sport pressure plates use exclusive diaphragm design to increase clamp load, reduce deflection and maximize clutch life. All diaphragms endure a four-stage, heat-treating process for unparalleled performance. ACT pressure plates have precision cover stampings to provide rigidity and consistency. ACT's 4-pad rigid race discs are made with high quality, ceramic friction materials. The chrome-moly hub is heat-treated for strength and durability. The lightweight, rigid design allows for quicker shifts and smooth, trouble-free service. With the 4-pad rigid race disc, engagement is harsher, but shifting is faster. The 4-pad rigid race disc is well-suited for the smaller disc sizes in smaller engines.