EBC XC Series Contour Brake Rotor MD1137XC The steel used in the EBC rotor blades is a special stainless blend with higher friction effect than normal heat treated stainless steel found on stock discs Boasts up to 10% improvement in friction effect improving brakes even further Weight of the X and XC series is reduced by 5-10% by using a 6 only button drive system on a lightweight alloy centre hub, which once again grabs the lead over stock parts The SD-System uses a square sided rivet with many advantages The SD-System of square sided buttons means that the rotor can expand inwards and outwards unrestrained and that perfect rotor functionality is retained at any speed or load