Allows for the operation of various pulleys, and drive belt accessories, with the use of a single belt Creates a secure point of contact with the pulley, which allows for traction Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional GM Engineers design and validate OE parts specifically for your Chevrolet, Buick, GMC, or Cadillac vehicle Original equipment parts are designed to work with your GM vehicle safety systems -- aftermarket replacement parts may not meet the same OE safety regulations, depending on the part type GM regularly updates production and service part designs to integrate new materials and technologies