This is a nice set of clean, narrow speedway design AP  billet aluminum, removable bridge, externally plumbed, radial mount, race calipers w/ 4 piston (coated aluminum alloy) differential bore 44mm / 48mm zero drag design for 295mm-323mm x 25mm-32mm rotors. Part #CP5835. Pad shape PFC #7700 / AP 2279D50  This set has been rebuilt and not raced since. Very light weight, very rigid. These have larger pistons (more clamping power) than the comparable model from Brembo. New cost over $2200 each! Rotors are new AP, CP3837-104D/ 105D 304mm x 25mm for AP D50 pad shape.
Great BMW set up.