Just today, a young woman out walking her dog intercepted me to ask if I’d seen her other dog, who had gone missing. A few minutes later, I passed the house of a second woman, older, waiting for her canine pal to wander back from his unescorted tour of the neighborhood. (He returned while we were talking). “I look after my dogs,” she said, “but they keep getting out.” The distress and heartbreak of being separated from a lost, much-loved pet is one of the worst feelings out there, which is why the new RoamEO Pet Location GPS System ($400) is worth barking about. The same global positioning satellite technology used in cell phones and navigation is put to work here to pinpoint your dog’s location. The dog wears a specially enabled collar that works with a locator device that shows you, via LCD screen, where he is and where he’s heading next. Best of all, you get to set the geographical parameters, or virtual “fence.” This distinguishes your dog’s allowable roaming range from his out-of-bounds territory. As soon as the dog steps out of bounds, an audible alert is emitted by the device and you’re off to retrieve him with the help of your RoamEO screen, which can display your vagabond pup’s whereabouts within one mile in all directions. With the purchase of additional collars ($175), you can track up to three pets simultaneously; they’ll appear in different colors on the screen. This extraordinary invention isn’t cheap, but it comes with a locator screen, one GPS collar and an AC adapter. I know what you’re thinking: If you use it for your small child and your dog, it could be quite a deal.