Product Details: Equip your semi to be Ready for the Road Ahead™, with the Dayco 1.1" x 56.5" Poly Rib® Heavy Duty Serpentine Belt, a crucial belt to quietly generate stable electricity. To supply power to a vehicle's accessories, this replacement belt works with multiple tight pulleys and the alternator to convert mechanical energy into electrical power. Fashioned with modern EDPM rubber materials to reduce how often a belt should be changed. FleetPride is your First Click in Heavy Duty®.