Horlicks transition modulator : price, one shilling : the keys to health / Horlicks Malted Milk Company.

Cardboard device which functions as an aid in making music. Sliding the central part through the envelope displays whether there should be sharps or flats related to the note in question. It advertises Horlick's malted milk drink as a good source of nourishment and an excellent body building food. The pack is illustrated on the back of the item.