The sheng is made up of a collection of 17 to 37 vertical bamboo pipes  of different lengths which are mounted on a wooden base (originally made of calabash) which also doubles as the wind chest. Inside each pipe is a brass reed and sound is produces by blowing and sucking air through a pipe connected to the base. The air travels from the base to the bamboo pipes and the player selects the notes to play by pressing keys near the base. 

As the oldest example of a free reed instrument, it is thought that the sheng might have inspired the invention of free reed instruments in the West, such as the harmonica, accordion and reed organ. In the case of the sheng, the reeds are traditionally tuned using a compound that includes mercury – this would account for the alleged peculiar behavior of some older sheng players (!).