Transposition gizmo the amazing instant key finder. Find keys quickly and easily with this simple to use transposition gizmo, The disc in a clamshell case enables you to find keys quickly and easily, Locate the original key on the inner ring, slide the inner disc around until the original key lines up with the new key on the outer ring. Now simpy read off the various notes in the new key against the relevant notes from the original key. Bingo