J013 pressure plate features an exclusive diaphragm design to increase clamp load, reduce deflection and maximize clutch life while maintaining stock to moderate pedal effort. All diaphragms endure a four - stage, heat - treating process for unparalleled performance. ACT precision pressure plate cover stampings provide rigidity and consistency while precision machined pressure plate castings absorb heat. ACTs Heavy Duty pressure plates increase clamp load by 20 to 50 percent. ACTs Heavy Duty pressure plates are recommended for use with a street or race disc.