The Gates Heavy Duty Automatic Belt Drive Tensioner is designed to provide superior performance and reliability for Volvo and Mack . This tensioner features labyrinth seal technology to prevent contamination of internal parts, double row bearings to carry more load and last up to three times longer than two separate bearings, and a damping mechanism to provide maximum stability, reduce vibration and increase service life. The machined steel pulley reduces surface wear while shielding the internal bearing from external contaminants and damage. FleetPride is your First Click in Heavy Duty®.