Dayco Drive Belt Tensioner PulleyFeatures: Designed to replace serpentine and V-belt idler and tensioner pulleys Reduces vibrations and therefore prolongs belt life Spun steel construction Three dimensional computer aided design (CAD) and finite element analysis (FEA) ensure the optimal design and maximum structural integrity Comes with lubricated bearings and high temperature seals for maximum performanceDayco No Slack Idler/Tensioner Pulleys are built with smoother surfaces and tighter dimensional tolerances which translates to less vibration and therefore longer belt life. Lifetime lubricated ball bearings and double high temperature seals assure peak bearing performance the most critical element of a pulley's service life. This specific flat serpentine belt driven steel pulley contains a specially formulated e-coating comparable to OE plating that resists corrosion and wear resistance under harsh environments.