The 58500 hook fits idler pulleys with 13mm, 14mm, 15mm, 16mm, 18mm, and 19mm hex sizes and is compatible with both 3/8" and 1/2" square drive tools. 58430 Shaft Type Seal Puller with 58500 Hook for Shaft/Seals, Universal Seal Removal Tool for Camshaft and Crankshaft Seals, 56750 Blind Oil Seal Puller, Automotive Repair Tool.