Fitment: for BMW 228i 14-16, for BMW 320i 13-18, for BMW 328i 12-16, for BMW 428i 14-16, for BMW 528i 12-16, for BMW X1 13-15, for BMW X3 13-17, for BMW X4 15-19, for BMW X5 16-18, for BMW Z4 12-16.
Material: This belt tensioner is made of metal material, which is wearable, durable and scratch-resistant.
Function: A belt tensioner is a system that guides the serpentine belt and the timing belt on a car engine. The function of a pulley and a tensioner is to limit the belt slip. The belt tensioner can be a mechanic (spring-loaded) or hydraulic.