This is a new 1/2" drive 54mm socket that has been CNC machined to add 3 notches for use on the full float rear wheel bearing nut. This single tool can be used to loosen/torque the front and the rear axle wheel bearing nuts. The interior of the nut was also machined to better fit the Toyota 54mm hub nut.
This tool is a 3rd party machined piece that Wits' End is now carrying on hand as a convenience. The original OTC version is no longer available and this is the next best option.