A tamper-proof identification device from VeriChip Corporation, Delray Beach, FL (www.verichipcorp.com) that is implanted under the skin of a person for medical or security purposes. Using RFID technology, a wand is waved over the skin to pick up the unique number stored in the chip, which is no larger than the tip of a ball point pen. In October 2004, the chip was officially approved for U.S. medical applications by the Food and Drug Administration. In an outpatient procedure, the VeriChip is implanted with a small incision and local anesthesia.