EBC Brakes RSD019BLK Black Chrome Full Floating Rotor The all new EBC Brakes black chrome rotor for big twins is a polished stainless and black chrome center hub finish range of fully floating brake discs/rotors for all US built big twins and cruisers As with all EBC big twin rotors, all components and hardware are stainless steel but in addition to the high lustre polished stainless steel center hub, we have applied a black chrome finish to improve the cosmetics The outer rotor ring or blade is from heat treated and tempered stainless steel with a diamond ground finish mounted onto the centre hub with EBC's patented SD system square drive rivet hardware The SD system buttons which appear circular are flat sided and mount into square pockets in the center hub and rotor blade allowing the rotor blade to expand and contract freely under heavy braking, totally eliminating brake vibration and rotor distortion Front designs are 5 button to reduce weight but rear units are a beefy 10 or 12 button design for much heavier abuse and braking