The organ keys are unusual in that they extend downwards below the pivots, instead of the normal bell-crank arrangement. The space normally occupied by the horizontal levers is enclosed by a plate incorporating a tune indicator. The tune-sheet, which is intended for a twelve-air drum, bell and castanet box, is associated with Ducommun Girod (Ord Hume, Op. Cit. Appendix II, fig 24) and has also been seen on a French musical box of L'Epee type.