It's summer. But is it time to let the toddlers run wild? If you have a small child or a big dog you need to keep track of, the Trax Play GPS tracker ($99) is a no-nonsense solution. It's a small plastic box you can track from a smartphone, giving you an update every 15 seconds as to the location of your loved one—as long as they aren't indoors. For more flexible tracking, though, we prefer devices with two-way communication like the LG Gizmopal 2 ($79.99) and Verizon's GizmoGadget .

Design and Features
The Trax Play is a small square box, measuring 2.2 by 1.5 by 0.4 inches (HWD) and weighing just 0.8 ounces. It slips easily into any pocket, and comes with a rubbery belt/collar clip. Made of blue or magenta and white plastic, it's dustproof and splashproof, but not waterproof; you can let it go under the playground sprinklers, but not for a dip in the pool. A standard micro USB port on the bottom is for charging, and there's a power button on the top. A single, slightly incomprehensible LED is its only display. Various patterns of blinks tell you whether it's charged, on, connected to the network, or has a low battery, although you'll need to use the manual to decipher them.

The tracker works with an Android or iOS app that can link together multiple phones and trackers within a family, showing them all on a map. You can set geofences to receive alerts when a tracker enters or leaves a designated area. You can also look at the history of where the tracker has been over the past day, although if your child or pet has been running in circles, it can be a little difficult to figure out where they went first. Otherwise, it's pretty painlessly plug and play.

Price and Performance
The device has three service plans, all for unlimited use: about $54 for 8 months, $72 for 16 months, or $96 for 24 months. Support is run from Sweden, which gives me a bit of pause—I prefer US-based support—but they responded to my emails within two days.

Satellite GPS is used for tracking, which is limited. That means the tracker pretty much totally cuts out when you're inside a building, going into standby mode. It also has some trouble in dense urban environments. Out in front of the PCMag office in midtown Manhattan, it couldn't find a location lock until I walked to the corner. But once locked on, it updates every 15 seconds. I found that it was usually accurate to within about a 50-foot radius, enough to tell that your child is at the playground, but not necessarily where they are at the playground.

The company says the Trax Play has 8-10 hours of tracking on a charge, though we found it to have about double that amount. Still, that's only a day at most. You can reduce the tracking frequency to once every minute to extend battery life, but you'll certainly have to recharge it daily. Because of its short battery life, it's best to slip the tracker into your child's pocket when needed and take it back out when you're done.

Conclusions
The Trax Play is a fine solution if you need to track children or pets that can't talk back. But in my kid-tracking experience, being able to open a conversation is critical. That's how you find out exactly where your child is on the playground, or the fact that your elderly relative has fallen and can't get up.

With that in mind, I strongly recommend Verizon's LG GizmoPal 2 (for ages 4-7, or for sufferers of severe dementia) or GizmoGadget (for ages 6-12, or for more competent folks) as the best wireless tracking devices. Each adds a speakerphone element with limited phone calling, which really changes the game. For pet tracking, the Whistle GPS Pet Tracker is our Editor's Choice; it has more pet-oriented software and much, much longer battery life.