The tuba is the lowest of all brass instruments. It has an upward-pointing bell, a beaker mouthpiece, three to seven valves and, due to its wide length and the correspondingly strongly conical tube, generally made of brass, belongs to the bow-horn family. The main feature of the tuba is the strong expansion of the tube (wide scale) in a ratio of up to 1:20 from the mouthpiece to the bell of the instrument. When seated, the tuba rests on the thighs of the player, for smaller tuba players with particularly large instruments also on the chair itself. A special stand, shoulder strap or tuba belt is required to play while standing. The funnel usually points upwards and mostly slightly to the left in the version with rotary valves, or to the right in the version with Périnet valves (as seen from the player).