The Vibraslap or Rattle Clap is also called a Donkey Call. It is meant to emulate the original sounds made by rattling the loose teeth in a dried out horse's jawbone. Inside the wooden resonator are a number of metal teeth. By striking ball on palm of your hand, the teeth rattle against the wood creating a high pitched rolling rattle. Perfect for special effects; and so much cleaner than that old horse bone. Great noise maker.