The sound record employed by the disc-type music box is a circular metal sheet which carries a musical composition. This is achieved by perforation or projection extending from the underside of the disc. The music box is equiped with a comb which is plucked by the protruding pins on the disc in connection with a set of star wheels or levers.
In the late 1880s the Symphonion Musikwerke located in the suburbs of Leipzig, Germany, was the leading manufacturer with products ranging from tiny music boxes as children's toys, to musical hall clocks to large, up-right, coin-operated boxes made specifically for commercial use.
In 1886 the first instrument with interchangeable discs was introduced. From then on the disc-type was manufactured in such a way that all discs could be played on any machine of the same make, size and type of musical comb.
As different tunes could be played on the same instrument without too much disruption, the disc-type music box was much more flexible and convenient than its predecessor, the cylinder-type. Due to the louder volume, better availability and lower price of the discs and music boxes, as well as skillful marketing of the manufacturers, the disc-type music box soon took over the market.sources