 Mosley spent most of his career on trombone, but also invented an instrument called the slide saxophone, which had both the slide portion of a trombone and a saxophone mouthpiece.The instrument is prominently featured in his 1940 recording "The Man with the Funny Little Horn".He recorded for Decca in 1940–1942, Sonora in 1946, Penguin in 1949, Columbia in 1959, and Pizza in 1978.