“Race” (TD7R)2 ceramic rigid discs The Clutch Masters FX725 is a 7.25" (184mm) Twin Disc clutch and is the ultimate in twin disk performance for engines/transmissions with smaller bell-housings that are focused on drag racing. Clutch Masters FX725 Twin Disc systems are developed from decades of experience in drag racing. Because of the minimal rotational mass the FX725 isn't ideal for the street but with improvements in friction material over the years we have been able to create a solution that can handle occasional street driving. The FX725 is designed to hold tremendous horsepower and torque, while maintaining reasonable peddle pressure to operate on the track.