Widely Compatible: PHILTOP Belt Tensioner Assembly Compatible with 335xi, 535xi, 535i xDrive, 535i GT, 535i, 335is, 335i xDrive, 335i, 135i. Make sure our Tensioner is perfectly compatible with your Car by 'AmazonConfirmedFit'. Improves engine performance: prevents belt slippage and noise, and extends the life of your engine belts. Reference Number # 11287563927 Stability performance: It can keep the drive belt or chain tight, reduce slack and jumping teeth phenomenon, make the engine and other mechanical parts run more smoothly and reliably. High-quality material: It is made of high-strength metal material, which is wear-resistant, corrosion-resistant and high temperature-resistant, and has a longer service life. Easy to install: Designed with standard size and interface, it is easy and convenient to install without professional skills. PHILTOP engine belt tensioner is a tool used in automobiles to keep the belt taut. Driving safety, engine life, fuel efficiency, and comfort are all enhanced by helping to maintain the proper belt tension and preventing the belt from slackening or falling off. Typically, an automobile tensioner consists of a tensioning pulley that aids in maintaining the proper belt tension and a tensioning mechanism that modifies the tensioning pulley's position to do so. To make sure they are functioning properly and to prevent failure, automotive tensioners typically need to be inspected and replaced on a regular basis. Tensioners can assist in maintaining optimum belt tension and preventing belts from slackening or falling off, which increases driving safety.Longer engine life: A tensioner may keep the belt at the right tension, reducing friction and wear between engine parts and increasing the engine's life. A loose or dislocated belt can generate friction and wear between engine elements.Enhances fuel economy: A belt with the right tension puts less strain on the engine, enhancing fuel economy.Enhances comfort while driving: A correctly tensioned belt lowers noise and vibration, enhancing comfort while driving.