Crystal Kantilan Gender. This pair of instruments is a crystal adaptation of the Indonesian gender. It is one of the main instruments used in Indonesian gamelan ensembles. It is tuned in a pentatonic “slendro” mode, which is one of the two traditional modes used in these ensembles. The pair is made of a female “ngumbang” and a male “ngisep”. When they are played simultaneously, they create a wave that is typical in the traditional gamelan ensembles.