A clapper is a basic form of percussion instrument. It consists of two long solid pieces that are clapped together producing sound. A straightforward instrument to produce and play, they exist in many forms in many different cultures around the world. Clappers can take a number of forms and be made of a wide variety of material. Wood is most common, but metal and ivory have also been used. The plastic thundersticks that have recently come to be popular at sporting events can be considered a form of inflated plastic clapper.