Dayco OAPs allow the alternator to freewheel when the belt speed drops and are engineered with one-way clutches that allows the rotational inertia of the alternator to overrun during any belt deceleration. Dayco OAPs, which are designed for long service life, decrease drive belt vibration and reduce belt slippage during rapid acceleration or deceleration, resulting in reduced stress on the drive belt and other accessories as well as increased alternator and drive belt life.