VeriChip

VeriChip is an injectable identification chip that can be inserted under the skin of a human being to provide biometric verification. VeriChip, manufactured by Applied Digital Solutions, is about the size of a grain of rice. It holds an identification number, an electromagnetic coil for transmitting data, and a tuning capacitor; the components are enclosed inside a silicon and glass container that is compatible with human tissue. The chip, which uses an RFID (wireless transmission) technology similar to the injectable ID chips used by animal shelters to tag pets, can be read by a proprietary scanner up to four feet away.
VeriChip was originally intended to function in much the same way a medical alert bracelet does by giving medical personnel life-saving information about a patient's history. It is now being used for security and automated data collection, as well as medical, purposes.