But the company behind the VeriChip, Applied Digital Solutions, says it is in the process of developing a chip that will contain GPS-tracking technology that would allow kidnap victims to be tracked with satellites. (The company says it is exploring a market in Latin American countries.)
Some experts are skeptical, saying the technology has substantial hurdles to overcome before such a device would be viable. Among them: making a gadget small enough to implant, and finding a way to charge the battery that doesn't involve plugging yourself into an electric socket.
While it will no doubt be a few years before chip implants rival cellphones as a must-have wireless accessory, there are a few options available. In November, for example, a company called Wherify Wireless began marketing every kid's worst nightmare: a "GPS Child locator" wristwatch that allows parents, via the Web or a phone call to a special hotline, to home in on their kids and pinpoint their exact current street address.
The watch, which sells for $400 plus a $25 to $50 monthly fee, operates on the Sprint PCS cellphone network and includes a 911 call button. (It comes in "Planetary Purple" and "Galactic Blue.")
Other options include the $400 "Digital Angel," which uses the AT&T wireless network and features a clunky, cigarette-pack-size unit that clips onto a belt. It also has a temperature sensor that can alert you if the wearer steps outside (or, say, into molten lava). It is sold by Applied Digital Solutions, the company that makes VeriChip.
In addition, there are car-tracking gadgets, like the $800 GlobalGuard, which can be installed in vehicles to keep tabs on anyone from adventurous teenagers to errant spouses to executives in danger of abduction. The device is available through Satellite Security Systems in San Diego.

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