Product Details: Update your semi with a quiet belt that generates stable electricity, with the Dayco 1.1" x 81.5" Poly Rib® Heavy Duty Serpentine Belt that ensures you're Ready for the Road Ahead™. 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. Crafted with state-of-the-art EDPM rubber materials to reduce how often a belt should be changed. FleetPride is your First Click in Heavy Duty®.