A microchip, also called a transponder or a tag, is an electronic system for the automated detection of animals. The transponder size is 2 x 12 mm and is enclosed in a tissue-compatible glass case, which includes an antenna coil and an passive chip with a preprogrammed and stored identification number.

Each animal worldwide receives its own unique identification number, which consists of a 3-digit country or manufacturer code and a 12-digit identification number.

The country code (for example 276 for Germany) provides identification of the country of origin. Manufacturer codes can also be used in place of country codes (for example ** 934 ** for Tierchip Dasmann).