Wrench fastens to most popular pinion flanges and companion flanges to hold when setting bearing preload and tightening retaining bolt or nut. Wrench has provisions to work with 1/2" or 3/4" drive tool. Center hole is 2" to clear most sockets. Universal slotted bolt patterns for 1/4", 5/16" and 3/8" fasteners for most AMC, Dana, Ford and GM yokes.