Prepare your semi to be Ready for the Road Ahead with a quiet belt that generates stable electricity, with the Dayco 1.66" x 85.24" 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 .