What a great name! The first time I heard “Gizmo Key” I thought, “That key must have gears and pulleys and ropes and cam action, it must be so cool!”
How disappointed I was to find out that it is just a little spatula stuck on the low B key.
It was created by Verne Q. Powell flutes when Jean-Pierre Rampal complained the B foot flute made the higher notes too difficult to hit. It is intended to make the 4th octave C easier on B foot flutes, and is now on almost all of them. Play the 4th octave C and put down the gizmo key on the low B key. It should only close the low B key and make the note a bit more full and stable.
~ Erik Nugent