Used to Install the Main Stretch Belt on Extra Deep Double Pulleys. Inside of the tool is designed to fit securely on the front side of pulley. The tool holds the belt on the pulley as the engine in rotated clockwise to install the belt. Helps prevent damage to the belt or pulley during installation. Works on 2011 and newer Ford 3.5L EcoBoost and 3.7L engines, as well as 2019 and newer GM 5.3L and 6.2L engines.