These are the very rare Brembo aluminum calipers with 3.0 inch bolt spacing and 48mm pistons. Essentially these are an "S" caliper with the smaller 3.0 inch bolt spacing. Direct bolt on for 356 front (w/ disc brakes), 65-77 911 front/rear, 78-89 911 rear w/ 20mm wide rotors, and 914 front/rear. Completely refurbished with new pistons, seals, and bleeders. Sold in pairs (right and left side), pad springs and pins included. Weight is 4 lbs. each. Please specify for solid or vented rotors when ordering. Extremely popular for rear spec 911 racing applications when used with Boxter front conversions listed above. Rotor discs are available as an option. All 356, 911/912 (65-68) rotors are solid. 911 (69-89) rotors are vented, cross drilled, and have directional spiraled vanes (left and right specific). All rotors offered below are high quality German made, sold in pairs.