Sackbut

A sackbut is a type of trombone from the Renaissance and Baroque eras, characterised by a telescopic slide that is used to vary the length of the tube to change pitch. Unlike the earlier slide trumpet from which it evolved, the sackbut possesses a double slide, which allows for playing scales in a lower range. Sackbuts adjust tuning at the joint between the bell and slide. The sackbut differs from modern trombones by its smaller, more cylindrically-proportioned bore, its less-flared bell, and in the lack of a leadpipe, water key, slide lock, and tuning slide on the bell curve.