The SmartTag microchip is a permanent pet ID with a one-time lifetime registration that also comes with a visible metal SmartTag pet ID. The microchip itself has no internal energy source and will last the life of your pet. It also has an anti-migration feature to help ensure that the microchip will stay in place, making it easy to locate and scan if your lost pet is brought to a pet hospital or shelter. They can scan the SmartTag microchip to read its unique ID code. This is the number used by SmartTag to identify the pet and retrieve your contact information, which is used to contact you and reunite you with your pet.