The unique beauty of trombone music comes from the glissandro or sliding sound. The telescoping slide allows a trombonist to rapidly move through a series of consecutive tones in a scale-like passage. Instead of using valves, notes are played by position of the slide. This may be tricky at first but comes with muscular memory. Working the slide in and out can produce bass and treble notes in the same breath and gives trombone music a powerful speed and fluidity.