Product Details: Ensure your semi is Ready for the Road Ahead™ with a quiet belt that generates stable electricity, with the Dayco 1.38" x 60.83" Poly Rib® Heavy Duty Serpentine Belt. 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®.