This instrument is also know as the vibra-slap or rattle trap, and is made to replicate the sound of rattling teeth in a dried out jawbone of a donkey or zebra, for example. In this version, small metal pins rattle between the sides of the metal chamber when the ball end is slapped. The metal version actually produces a mellower sound than its wooden counterpart. A highly unusual rattling sound is a great novelty and very popular among professional percussionists. Great for background "ambient" percussive sounds in any style of music.