Bangu is a short drum. The drum body is made of hardwood, such as colored wood, birch, pagoda tree, Sang Mu, beech or teak, and is made of five thick planks. The drum body is 25cm in diameter, but most of them are wooden boards, and the vibration of the drum head is only 5? 10 cm, the drum bore is splayed, and the drum edge is 9.5 cm high. The drum skin is made of cowhide, and it is tightened on the whole board to the bottom edge. The protruding part of the skin, also called "drum light", is the part of percussion pronunciation. The pronunciation of the drum depends on the size of the drum hole and the tightness of the skin. In order to keep the tension of the drum skin, more nails are nailed on the drum and iron rings are tied at the bottom. Castanets are percussion instruments. Spread Spanish folk percussion instruments. It was mainly used to accompany songs and dances, and later it was also used in European art music, using two pieces of shell-shaped ebony to make sounds.