In order to run dual calipers for a hydraulic hand brake with an independent reservoir master cylinder, this bracket allows you to adapt 2 piston Z32 twin turbo calipers to E46M3 328x20mm rotors. Installs on the removed drum parking brake's mounting provisions in E46M3 trailing arms, which are a popular swap on non-M cars because of the larger hubs & axles the E46M3 rear trailing arms allow. NOT compatible with 330ci trailing arms. Compatible with stock E46M3 foot brake calipers and rotors OR Z32 fot brake setup setup sold separately. CNC aluminum with gold anodizing, laser logos, and 12.9 grade hardware. Pair with our reproduction calipers, hydrobrake & hard lines and fittings set, all sold separately. Drum parking brake must be removed.