Mbira (thumb piano) Also called Thom by the Anuak. The instrument called the thom by the Anuak is commonly called the sansa, mbira,, or thumb piano by writers about African music. A thom is a small wooden box comfortably held in the hands of the player. Ten, eleven, or twelve wire bars made of umbrellas stays extend over a bridge and are held in place by a metal clamp. At the base of the bars are metal strips wound loosely around the bars. They are thin windings from a tin can and cause rattling and buzzing sounds when the bar is plucked. Progress is threatening the survival of thom. Umbrellas are now being manufactured with plastic stays which lack the resonance of the metal ones. The thom is played with the thumbs of both hands. The player will at times close a hole in the bottom of the instrument to slightly change the tonal quality. A performer will change the intervals used for a song by adjusting the bars, sliding them over the bridge and through the clamp, effectively shortening the vibrating members.