This is a nice set of clean, narrow speedway design AP  billet aluminum, removable bridge, internally plumbed, radial mount, race calipers w/ 4 piston (coated aluminum alloy) differential bore 44mm / 48mm
zero drag design for 300mm-320mm x 25mm-32mm rotors. Part #CP5835. Pad shape PFC #7700 / AP 2279D50  This set has been race prep'd w/new seals, ready to race. Very light weight, very rigid.
These have larger pistons (more clamping power) than the comparable model from Brembo. New cost over $2200 each!