Isaac Daniel calls the tiny Global Positioning System chip he's embedded into a line of sneakers ''peace of mind.'' He wishes his 8-year-old son had been wearing them when he got a call from his school in 2002 saying the boy was missing. The worried father hopped a flight to Atlanta from New York where he had been on business to find the incident had been a miscommunication and his son was safe.

Days later, the engineer started working on a prototype of Quantum Satellite Technology, a line of $325 to $350 adult sneakers that hit shelves next month. It promises to locate the wearer anywhere in the world with the press of a button. A children's line will be out this summer.

''We call it a second eye watching over you,'' Daniel said.

It's the latest implementation of satellite-based navigation into everyday life — technology that can be found in everything from cell phones that help keep kids away from sexual predators to fitness watches that track heart rate and distance. Shoes aren't as easy to lose, unlike phones, watches and bracelets.

The sneakers work when the wearer presses a button on the shoe to activate the GPS. A wireless alert detailing the location is sent to a 24-hour monitoring service that costs an additional $19.95 a month.

In some emergencies — such as lost child or Alzheimer's patient — a parent, spouse or guardian can call the monitoring service, and operators can activate the GPS remotely and alert authorities if the caller can provide the correct password.

But the shoe is not meant for non-emergencies — like to find out if a teen is really at the library or a spouse is really on a business trip. If authorities are called and it is not an emergency, the wearer will incur all law enforcement costs, Daniel said.

Once the button is pressed, the shoe will transmit information until the battery runs out.

While other GPS gadgets often yield spotty results, Daniel says his company has spent millions of dollars and nearly two years of research to guarantee accuracy. The shoe's 2-inch-by-3-inch chip is tucked into the bottom of the shoe.

Experts say GPS accuracy often depends on how many satellites the system can tap into. Daniel's shoe and most GPS devices on the market rely on four.

''The technology is improving regularly. It's to the point where you can get fairly good reflection even in areas with a lot of tree coverage and skyscrapers,'' said Jessica Myers, a spokeswoman for Garmin International Inc., a leader in GPS technology based in Kansas. ''You still need a pretty clear view of the sky to work effectively.''

Daniel, who wears the shoes when he runs every morning, says he tested the shoes on a recent trip to New Jersey. It tracked him down the Atlantic Coast to the Miami airport and through the city to a specific building.

The company also has put the technology into military boots and is in talks with Colombia and Ecuador, he said.

But retail experts say the shoe might be a tough sale to brand-conscious kids.

''If (parents) can get their kids to wear them, then certainly there is a marketplace. But I think the biggest challenge is overcoming... the cool marketplace,'' said Lee Diercks, managing director of New Jersey-based Clear Thinking Group, an advisory firm for retailers.

The GPS sneakers, available in six designs, resemble most other running shoes. The two silver buttons — one to activate and one to cancel — are inconspicuous near the shoelaces.

The company is selling 1,000 limited-edition shoes online and already has orders for 750, Daniel said.

Parents who buy the pricey kicks don't have to worry about their kids outgrowing them fast. This fall, the company is unveiling a plug-and-wear version that allows wearers to remove the electronics module from their old shoes and plug it into another pair of Daniel's sneaks.