Product Details: Ensure your semi is Ready for the Road Ahead™ with a quiet belt that generates stable electricity, with the Dayco 0.828" x 63.5" Poly Rib® Heavy Duty Serpentine Belt. Thanks to its partnership with multiple tight pulleys and the alternator, this replacement belt is able to convert the mechanical energy from the engine into electrical power for accessories. Fashioned with modern EDPM rubber materials to reduce how often a belt should be changed. FleetPride is your First Click in Heavy Duty®.