A steel tongue drum, tank drum, or hank drum is a round steel slit/tongue drum in the idiophone family originally fashioned from a propane cylinder. A steel tongue drum can be made from an empty, often 20-lb propane tank. The tank is flipped over and the base is cut or knocked off. Seven to ten tongues are then cut radially into the bottom of the tank, forming the top of the instrument. A steel tongue drum can also be made from a new unused tank head. The tongues can be tuned by the maker by varying the length of the cuts, or by adding weights, often neodymium magnets, to the tongues. Although steel tongue drums are often tuned to pentatonic scales, they can also be tuned to the diatonic scale, the chromatic scale, or any set of notes the maker chooses. The instrument is played with the fingers or with mallets. It boasts a pleasant, bell-like tone.