The term 'kind of trombone' refers to the three main types of trombones: SLIDE, ALTO, and VALVE. The SLIDE trombone is a traditional type of trombone that uses a SLIDE to change the length of the instrument's tubing, allowing the player to produce different notes. The ALTO trombone is a smaller version of the SLIDE trombone, and is usually pitched in E-flat. The VALVE trombone is similar to a trumpet, as it uses valves instead of a SLIDE to change the length of the tubing.