A nipple gong has a central raised boss or nipple, often made of a different metal to the rest of the gong. They have a clear resonant tone with less shimmer than other gongs, and two distinct sounds depending on whether they are struck on the boss or next to it. They most often are tuned to various pitches.
Nipple gongs range in size from 6″ to 14″ or larger. Sets of smaller, tuned nipple gongs can be used to play a tune.
Nipple gongs are used in Chinese temples for worship.
In Indonesian gamelan ensembles, instruments that are organologically gongs come in various sizes with different functions and different names. For example, in the central Javanese gamelan, the largest gong is called gong ageng, ranges in size up to 1 meter in diameter, has the deepest pitch and is played least often; the next smaller gong is the gong suwukan or siyem, has a slightly higher pitch and replaces the gong ageng in pieces where gong strokes are close together; the kempul is smaller still, has a higher pitch, and is played more frequently. The gong ageng and some gong suwukan have a beat note.
