The device is powered externally as needed. inside the device is a coil and a capacitor. When the RFID chip is exposed to an electromagnetic field the same frequency as the coil is tuned to then the coil takes some of the energy from this field and charges the capacitor which then powers the chip long enough to transmit, using frequency variations on the same coil that it used to get the power, to transmit a code. Your personal ID number. This is the same system used by EZPass but with larger coils.
In biblical numerology 777 is God and 6 is man so 666 is man trying to be god. One way man tries to be god to to control everything through our own technology.
This calls for wisdom. If anyone has insight, let him calculate the number of the beast, for it is man's number. His number is 666. Revelations 13:8