Removes damaged thread and taps a new oversize thread Fits idler pulleys requiring 13mm, 14mm, 15mm, 16mm, 18mm, 19mm hex and both 3/8" and 1/2" square drive sizes The unique tapping tool ensures the new thread will be perpendicular to the gasket surface to prevent leakage For more information check the main Lisle tool- 58850 Replacement part for Lisle tool- 58850