Our E-Matrix disc brake pads are based around our Race Matrix pad compound but modified for greater endurance, adding a unique blend of kevlar, ceramics, heat resistant resins and friction materials to be able to withstand the increased weigh and speeds of electric bikes and demanding riding styles such as downhill. For use with the SRAM Code R, Code RSC, Guide RE systems. Note - Despite sharing the Guide name, the RE disc brake pads are not compatible with SRAM Guide R, RS, RSC and Ultimate brake calipers.