ACT's most popular Heavy Duty pressure plate. ACT Heavy Duty 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. The ACT performance street rigid-hub discs feature premium organic materials with high copper content for better heat transfer and steel-backed lining for greater burst strength and durability. The chrome-moly hub is heat-treated for strength and durability. Rivet design and materials are carefully selected for maximum strength. These discs are the minimum weight street disc for faster shifts. ACT's street rigid-hub discs provide race-proven performance with street manageability.