The OE No.:  0K551 -12740A   0K88R -12740 Tensioners are belt tensioners used in automotive drivetrains. The structure tensioner is mainly composed of a fixed casing, a tensioning arm, a wheel body, a torsion spring, a rolling bearing and a spring bushing, etc. It can automatically adjust the tensioning force according to the different tightness of the belt, making the transmission system stable, safe and reliable. More tension pulley models :