The microchip is a device used for permanent identification for your pet. It is about the size of a grain of rice and is placed under the skin between the shoulder blades. Veterinary clinics and animal shelters have scanners that are able to read the chip's number (the number being unique to your pet). Your contact information is in a national database and if your pet is ever lost, you can be contacted and reunited. There is a successful recovery every 6 minutes. It is still important your pet has a proper collar tag identifying you as its owner.