The Dayco Serpentine Automatic Belt Tensioner is designed to provide reliable belt tension, consistent performance, and long life. This tensioner features a zinc-coated mounting bolt that resists rust, a steel pivot tube on specific designs for enhanced stability, and thermoplastic rubber spring slot plugs and rubber O-ring seals to help keep contaminants out. It is the perfect choice for reliable belt tension and consistent performance. FleetPride is your First Click in Heavy Duty®.