Vehicle Fitment: AUTOSITY Belt Tensioner Assembly Replacement for 328i, 525i, 525iT, 528i, 530i, M3, X3, X5, Z3, Z4, 330i, 323Ci, 323i, 323is, 325Ci, 325i, 325is, 325xi, 328Ci, 328i. Make sure our Tensioner is perfectly compatible with your Car by 'AmazonConfirmedFit'.Enhances engine performance by reducing noise and belt slippage and extending the life of your engine belts. Referral Number 11281427252Performance in terms of stability: It can maintain the drive belt or chain tight, eliminate the slack and leaping teeth phenomena, and improve the smoothness and dependability of the operation of the engine and other mechanical elements.High-quality material: It is constructed of high-strength metal, which has a longer service life and is wear-, corrosion-, and high temperature-resistant.Simple installation: Because it has a standard size and interface, installing it is simple and comfortable even for people without technical expertise.