Product Details: Keeping you Ready for the Road Ahead™, the Dayco 89440™ Auto Adjust Heavy Duty Automatic Belt Tensioner is meticulously made to the strictest design specifications. This belt tensioner features a high-strength cast aluminum body designed to keep contamination out and resist cracking, fatigue, and deformation. In addition, the use of advanced material serves to reduce weight when compared to regular belt tensioners, while also providing added strength and durability. The Dayco heavy duty belt tensioner boasts multiple patented components which are engineered to handle the higher torque and power pulses exerted by today’s diesel engines. FleetPride is your First Click in Heavy Duty®.