A microchip implant is a small chip about the size of a grain of rice and contains a unique identification code. It is implanted painlessly under the skin at the back of the neck between the pets shoulders. In Ireland all dogs must be microchipped before sale by their breeder. When your pet is microchipped it is then registered to a national database, where vets and others in animal welfare can retrieve owner details and reunite them with their lost pets. Cats are not legally required to be microchipped, although it is invaluable in reuniting cats with their owners as each chip is unique to that pet.