ZM8-HDSS 2004+ Mazda RX-8 ACT HD Performance Street Disc Clutch Kit includes a pressure plate, clutch disc, release bearing, alignment tool, and pilot bearing. HD Pressure Plate:Clamping loads increase 20% - 50%. Pedal effort feels stock to moderate. SFI certified to ensure safety. SS Perfomance Street Disc:Recommended for street and light race use. Good dual purpose clutch for a daily driven street vehicle with weekend race use. Quicker engagement than stock, quiet operation, best organic friction material, improved hub and burst strength.