although victor's victrolas and similar record players could not play diamond discs (at best, only very faint sound would be heard, while the crude steel needle seriously damaged the groove) and edison diamond disc phonographs could not play victor or other lateral-cut discs, third-party suppliers came up with adapters, such as the kent adapter, to defeat this incompatibility, but typically with less than optimal sound quality. the brunswick ultona, the sonora, and the expensive "duo-vox" phonograph made by the piano manufacturer bush and lane were the only non-edison machines that came from the factory equipped to play diamond discs as well as victor and other 'needle-type' records, along with pathé's sapphire ball stylus hill-and-dale format that used a vertical groove that was u-shaped in cross-section. edison discouraged all such alternatives by cautioning on some of the record sleeves: "this re-creation should not be played on any instrument except the edison diamond disc phonograph and with the edison diamond disc reproducer, and we decline responsibility for any damage that may occur to it if this warning is ignored." the very good reason for such discouragement was that diamond disc grooves were too narrow and fragile to propel a soundbox across a record surface, as lateral machines did; edison's precise mechanical feed system on the disc phonograph for its weighted "floating" reproducer replaced that stress on its records.