Only the size of a grain of rice, a pet microchip is usually injected just under the skin at the back of the neck of your pet. The procedure is usually carried out by a veterinarian and is quick and painless. The chip carries information which is readable by a chip reader, particularly a code which can then be checked against an owners register which can then be used to trace the owner if the pet has turned up at a pound or the police in the event if goes missing.