Metallophone
A metallophone is any musical instrument in which the sound-producing body is a piece of metal (other than a metal string), consisting of tuned metal bars, tubes, rods, bowls, or plates. Most frequently the metal body is struck to produce sound, usually with a mallet, but may also be activated by friction, keyboard action, or other means. Metallophones have been used in music in Asia for thousands of years. There are several different types used in Balinese and Javanese gamelan ensembles, including the gendér, gangsa and saron. These instruments have a single row of bars, tuned to the  distinctive pelog or slendro scales, or a subset of them. The Western glockenspiel and vibraphone are also metallophones: they have two rows of bars, in an imitation of the piano keyboard, and are tuned to the chromatic scale. In music of the 20th century and beyond, the word "metallophone" is sometimes applied specifically to a single row of metal bars suspended over a resonator box. Metallophones tuned to the diatonic scale are often used in schools; Carl Orff used diatonic metallophones in several of his pieces, including his pedagogical "Schulwerk". Metallophones with microtonal tunings are used in Iannis Xenakis' "Pléïades