The serpent, a bass wind instrument, is notoriously difficult to play in tune. Because its finger holes are spaced based on where human fingers can reach, rather than where the acoustics of the tube dictate, the player must use their lips (the embouchure) to 'bend' almost every note into its correct pitch. Despite being made of wood, it uses a brass-style mouthpiece. It was the standard orchestral bass instrument for nearly 200 years until it was replaced by the ophicleide and the tuba.