The Amazing Transpo Gizmo Instant Key FinderPaperback, 1 February 2008

The transposition wheel in a clamshell case enables you to find keys in three easy steps: 1.Locate the original key on the inner ring. 2.Slide the inner disc around until the original key lines up with the new key on the outer ring. 3.Now simply read off the various notes in the new key against the relevant notes from the original key. Perfect for home or classroom.