Having your cat microchipped is an excellent way to make sure you and your cat get reunited should she ever get lost and is taken to a shelter or rescue.
A microchip is a computer chip about the size of a grain of rice that contains information linking you to your cat. Most shelters, rescues, and veterinary clinics have scanners that can detect and read all brands of microchips. But, to be clear, it is not a tracking device. Read Why Microchip Your Cat? to learn more about microchips.
To be effective, the information associated with the chip needs to be accurate. Michelson Found Animals Registry provides a free registry for all pet microchips. Even if you adopted cats from different organizations or your cats have different brands of microchips, you can register all of them here for free:
Also, the American Animal Hospital Association (AAHA) has a Universal Pet Microchip Lookup Tool that checks the databases of participating pet recovery services: