In Hungary, all dogs over 4 months of age and other small animals and horses must be permanently marked. The microchip is used for individual identification. The microchip is a device the size of a grain of rice, which is implanted under the animal's skin by the vet. The tiny tissue-friendly capsule contains an antenna and a microchip implanted with a unique 15-digit code. The implantation site in Europe is on the left side of the neck. The microchip does not transmit any signals on its own, but responds to radio signals from a special reader to display the serial number stored in the chip.