Some special registers with free reed pipes are expressive. The pitch of the framed free reed is fixed. Used as a hand-held free reed instrument. The most common type is a circular free reed aerophone. The recordings were issued on the "Free Reed" label in the '70s. The mangtong () is a Chinese end-blown free reed wind instrument. From 1880 through 1892, he focused on automatic player piano mechanisms, the free reed organette. Various free reed instruments appear to have been invented since antiquity. The harmonica is a free reed aerophone, also often made from brass. Each pipe contains a free reed, which is also made of bamboo. The leaf of the "Eucalyptus" gum tree is used as a hand-held free reed instrument. A less-common type of reed construction is the "free reed". The sheng is a Chinese mouth-blown free reed instrument consisting of vertical pipes. Free reed instruments have been of growing importance since their development in the nineteenth century.