A singing bowl is a metal bowl that rings when you strike it or rub the rim. Sets in the shop include the bowl, a cushion, and a wooden mallet. Rest the bowl on the cushion so it can vibrate. A short strike gives a clear tone. To keep the tone going, press the mallet lightly around the outside of the rim and move in a steady circle.
Larger bowls usually sound lower. A pair played together gives two pitches instead of one. These are instruments for a table or the floor, not medical devices.