Kepyak: Indonesia musical instrument

The kepyak is a percussion musical instrument that is played by the dalang of a wayang performance in Java. The musical instrument is a struck idiophone that is made up of many bronze or iron plates affixed by strings or a single plate that the dalang performs having a small mallet held between the toes of his right foot. The musical instrument is placed on the side of the keprak, a wooden box that also can be played directly. The musical instrument can also be played with the use of a mallet, either in the hand in dance performance or in the foot in the wayang. The musical instrument used in dance performances is smaller than the one used in wayang. The use of this musical instrument is known as kepyakan.

source of picture: en.wikipedia.org

The musical instrument is used to signal cues to the gamelan to start or stop a pieces, or alter tempo or pathet. It has a unique sound that can be heard quite clearly during performance.