HC4-XXG6 kit features a MaXX pressure plate for the serious enthusiast. ACT MaXX 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 6-pad spring-centered race disc features a spring-center construction to properly damp torsional vibrations and resist failure under harsh conditions. ACT spring retainers utilize wraparound spring windows and thicker retainer stampings to provide spring support reduce stress concentrations and increase strength and reliability. With the 6-pad spring-centered race disc engagement is harsher but shifting is faster. The 6-pad spring-centered disc is recommended for larger clutch sizes to absorb more heat.