This dishing gauge is fully machined from big billets of aluminum to a final shape and accuracy that's as nice to use as it is to look at. Compatible with wheels from 20-29 inches and all hub combinations. Standoff feet are included for checking dish with the tire in place, even the big fat ones. The gauge uses a unique spring-loaded mechanism to drop the plunger. Press that little brass button on the front and the plunger will drop to the face of the hub. No archaic time-sucking threaded indicators here!