How it works
Pet microchips work similar to the way radio and TV stations work. That is to say that the broadcast station transmits electromagnetic waves and these waves induce a small electrical current in the antenna of your radio. For the microchip a handheld “scanner” sends out a much weaker signal. Now in your radio we need a battery or other electrical source to amplify the signal so it may be heard, but in the microchip the signal itself is enough to power the chip which in turn transmits its unique serial number back to the "scanner".
Not all pet microchips use the same frequency, and in order for the chip to be read by the scanner, they must use the same frequency. There are two predominate microchip frequencies in use, 125 kHz and 134.2 kHz. The frequency of 125 kHz is used in the United States while the rest of the world uses the 134.2 kHz ISO* chip. Most of the scanners in shelters in the U.S. only read the 125 kHz chips while most of the rest of the world only reads the ISO chip. For this reason we feel that folks that travel internationally with their pets should have both the U.S. chip and the ISO chip in their pet.