Park Tool WAG-5 Portable Wheel Dishing Tool
Park Tool claims that "The WAG-5 is the perfect wheel alignment tool for the race or home mechanic". While this is true, we have also found it's construction to be very durable and tolerances so precise that it perfectly suited for professional shop use as well. It make taking the measurements form each side of the wheel to determine centering of the hub a snap.
It will easily check both dish and offset of any 26", 29" or 700c wheel and disassembles in moments for travel or storage.