The Dayco 89114 Drive Belt Idler Pulley is a genuine accessory drive belt system component designed for direct replacement in engines. Made of steel with a maximum belt width of 0.6 rib, this pulley features two bearings with an inner diameter of 17 mm and an outside diameter of 60 mm. It is specifically designed for serpentine belts and comes with a free core charge. The pulley is designed to tension the accessory drive belt and is a crucial part of the engine's cooling and performance system.