The term “idiomount” refers to the fact that the tines on this instrument are their own mounting (unlike other most lamellaphones in which the keys are attached to a separate mounting). For a more coherent tone quality the bamboo keys have been shaped to put the most prominent overtone three octaves above the fundamental. Without this special shaping, that overtone would have appeared at some odd and unrelated pitch. Its two-sidedness makes this a nice instrument for two players, although one player can easily manage it as well.
A video of this instrument can be found among the demonstrations in this youtube playlist.