Chang Yi concern about the driving safety very much, so insist on providing the brake discs to customers after passing following strictly complete QC procedure. In order to assure the brake discs quality, all products need to be inspected by every quality check step for eliminating vibration problem. Our precision lathe grinding process ensure high precision in parallelism and thickness variation. Dynamically balance control is under 5gm-cm. Anti-rust treatment protect rotor bell surface from oxidation.