The alto horn (US English; tenor horn in British English, Althorn in Germany; occasionally referred to as E♭ horn) is a brass instrument pitched in E♭. It has a predominantly conical bore (most tube extents gradually widening), and normally uses a deep, cornet-like mouthpiece.It is most commonly used in marching bands, brass bands and similar ensembles, whereas the French horn tends to take the corresponding parts in symphonic groupings and classical brass ensembles.