Edelbrock Part #15035 Tensioner Upgrade Kit is engineered to handle the increased belt stress encountered in high horsepower Edelbrock applications. This kit is an upgrade for part #1572, #1575, #1591 & #1594 Edelbrock Supercharger Systems produced prior to February 2013 and are now included on all systems thereafter. Kits includes tensioner, tensioner mounting bracket, Gatorback drive belt and hardware.