Slingerland’s answer to the Ludwig & Ludwig Super-Ludwig, the DuAll was a Tone Flange model (solid maple, mahogany, or walnut) that featured the DuAll (parallel) strainer. This model was very short-lived because of patent infringement problems with the Ludwig & Ludwig Co. The short story is that in June of 1934, C. G. Conn (owner of Ludwig & Ludwig at the time) won a patent infringement suit against Slingerland. Slingerland was ordered to cease and desist from manufacturing the DuAll model and was also ordered to pay for any previous sales of their DuAlls. The interesting thing about this drum is that Rose Pearl was introduced in 1929, which is three years earlier than the introduction of the DuAll strainer. It is safe to say that this was a leftover solid maple Rose Pearl shell that was then outfitted with the DuAll strainer, probably between 1932 and 1934. Due to L&L’s legal victory, there were very few of these DuAll models manufactured, and therefore there are very few in existence today – probably less than 15. As of this printing, this is the only example in Rose Pearl.