This instrument derives its name from the cylinder onto which notes were arranged in a specific manner—using small metal projections or pins—to determine which tones would play. The system functions similarly to that of a music box, but instead of plucking a comb, the pins in this case open valves, allowing air to flow through tuned pipes or reeds. This mechanism is fundamentally and acoustically akin to that of an accordion.

The cylinder typically contained around 100 pins.

Manufactured by the Autophone Company of Ithaca, NY, this hand-cranked device was part of a line of barrel organs. The Gem was the smallest, most affordable, and most popular model in their collection.