R-4 Full Race Compound – Designed specifically for heavy-duty motorsports. The carbon based semi-metallic R-4 materials allow the pad to absorb tremendous amounts of heat and dissipate it at very even rate. Carbon Kevlar material warms up to race temperature quickly, which is quite helpful during restarts, and when track time is limited. When used with cast iron and steel alloy rotors, the R-4 compound requires minimal bed-in period. Throughout the entire heat range, the carbon kevlar material will give extremely consistent modulation and predictably. This is truly the most rotor friendly racing brake pad material ever. Good for road courses, oval track, rally, vintage racing, autocross, club events or professional racing events.