Because of its massive size and numerous curves, a tuba can trap a significant amount of condensation. A single rehearsal can result in nearly a cup of liquid inside the instrument. Unlike a trumpet, which has one or two water keys, a tuba often has many, or requires the player to literally spin the instrument 360 degrees to move the water through the 'slides' to an exit point. This 'tuba spin' is a common sight in orchestras during long rests.