The Monster All-in-One Master Bearing Race and Seal Driver, No. MST1108A, is a self-contained precision driver with a dial to adjust the three hardened jaws to seat races, bearing and seals. With no individual discs to sort through and, this tool keeps technicians at the fender and takes up less space in a toolbox. The driver is made of durable aluminum with a steel cap on the striker. The three-step jaw covers a range of OD/ID from 18.5mm to 89mm (0.72" to 3.5"). This tool is also available in a mini version (No. MST1108B) that covers the ranges of 9mm to 52mm.