All EBC rotors are made from OE spec grey cast iron, exactly as used on new car production and as many as we have tools for are BRITISH MADE wholly in our own UK foundry. Currently EVERY SINGLE ROTOR sold in Europe and the UK is BRITISH MADE and a majority of the designs specific to the USA are also BRITISH made.The British foundry is constantly expanding its in house tooled range but EBC like every brake manufacturer ....does need occasionally to buy some rotors in from approved sources to complete ranges in overseas markets. None of our competitors will ever tell you where their rotors come from and we at EBC are as disappointed as the rest of the world that cost pressure means there is not ONE foundry left in the USA to supply such parts, other brake brands when asked about origin will just sidestep the question. When we do buy rotors in, they are specified, sampled, tested for element analysis, grain structure, tensile strength, hardness and optimum ductility and tested 100 piece by piece to be perfect for runout on this in house machine. 3GD Series Sport Slotted Rotors; Rear; For FMSI Pad No. D1020; Vented; 5 Bolt Holes; 320mm Dia.; 48mm Height; 26mm Thick; 70.6mm Center Hole Dia.; DO NOT FIT UPGRADE PADS TO REAR OF VEHICLE UNLESS SAME UPGRADE FITTED TO FRONT, The Thermic Black coating? does NOT need to be removed before install. Do NOT use brake cleaner or any other method to remove Thermic Black coating from discs rotors. The Thermic black coating will be removed in the pad swept area by the brake pads with in the first 10 to 20 stops made after installation on the vehicle.The Thermic Black coating? is an anti corrosion coating for long resistance against rust. Attempting to remove Thermic Black Coating with brake cleaner or any other method is NOT covered under EBC warranty Rear GD Rotors 2009 theu 2010 CADILLAC STS 4.6 Performance