Must be used with ACT Flywheel P/PL Heavy Duty Light to moderate pedal effort, positive engagement; Available disc life extended by ACT's exclusive diaphragm design; Carefully engineered for improved durability, precisely assembled and accurately balanced; Recommended for street and race use; 100% clamp load tested and dynamically computer balanced for smooth high RPM reliability SB017 pressure plate features an exclusive diaphragm design to increase clamp load, reduce deflection and maximize clutch life. All ACT 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 Heavy Duty pressure plates increase clamp load by 20 to 50 percent. The Heavy Duty pressure plates are recommended for use with a street or race disc.