AP 4-Piston: Light weight cast aluminum • Fixed mount for minimal caliper flex • Differential Piston sizes (2x38.1/41.3mm) minimizes pad taper and maximizes even friction pressure • Anti Rattle springs reduce pad noise • Inner wiper and outer dust seals for everyday use AP Racing 328 x 28mm Rotors • Directionally Curve Vein Vented for maximum cooling • Cross Drilled and Slotted for aggressive pad bite and proper out-gassing • 2 piece modular disc Brake Pads • Pad Area 60.44cm squared x 2 per caliper • Pad material designed for high performance road and track use • Consistent friction co-efficient at low and high temperatures.