"Excellence in Performance", backed by the best one-year warranty in the industry! Perf Street Rigid Disc Smooth engagement, quicker shifts, increased gear rattle; Premium organic composite friction blended for high heat tolerance, increased burst strength, faster recovery from overheating and less wear of mating surfaces, rigid design may increase spline wear; Chromoly hub is heat-treated for strength and durability; Recommended for high horsepower street or race use; Steel-backed linings for higher burst strength, reduced marcel for quicker shifts 3000310 is a street rigid disc featuring premium organic materials with high copper content for better heat transfer and steel-backed lining for greater burst strength and durability. These discs are modified with reduced marcel for faster shift action to complement ACT pressure plates. The chrome-moly hub is heat-treated for strength and durability. Rivet design and materials are carefully selected for maximum strength. Lightweight, solid-hub design allows for quicker shifting and engagement. ACT's street rigid-hub discs provide race-proven performance with street manageability.