The saddle of a guitar refers to the part of the bridge that physically supports the strings. It may be one piece (typically on acoustic guitars) or separate pieces, one for each string (electric guitars and basses). The saddle's basic purpose is to provide the endpoint for the string's vibration at the correct location for proper intonation, and on acoustic guitars to transfer the vibrations through the bridge into the top wood of the guitar. Saddles are typically made of plastic or bone for acoustic guitars, though synthetics and some exotic animal tooth variations (e.g. fossilized tooth, ivory, etc. ) have become popular with some players. Electric guitar saddles are typically metal, though some synthetic saddles are available.