Wurlitzer bought De Kliest's interest in the business in 1909 and assumed operation of the North Tonawanda factory. The new company invested in new technology, resulting in the adoption of electric motors, and the music source was changed from pinned barrels to perforated paper rolls similar to a player piano roll. Some medium to larger organs such as the style 153, style 157 and style 165 have duplex roll frames, on which one roll plays while the other rewinds, allowing for continuous music. Each paper roll contained about 10 songs. During the Great Depression this was changed to 6 longer songs to save money on arranging.