A microchip is a permanent radio-frequency identification (RFID) chip implanted under the animal’s skin and read by a chip scanner or wand. Implantation is done with an injector that places the chip under the loose skin over the animal’s shoulder.
The advantages are obvious -- the process is quick and no more painful than a vaccination, the number is unique and the owners name and address are available on regional or national data bases so a dog can be returned quickly and safely.

Read more about microchipping.