Trax Play ($100) is a simple device that's great for parents who want to keep tabs on kids too young to wear a GPS watch or to carry a smartphone. Slip it into a pocket or backpack, and the tracker's geofencing capability will alert you when your child wanders outside an area that you designate through the companion app.
The app also offers a history feature, which lets you view where a tracker has been in the past 24 hours and an augmented-reality view to find your child easily in a crowded setting. Choose to receive location updates ranging from every 10 seconds to 60 minutes. You pay for service separately from the device, and the price drops the more service you preorder through Trax. Six months of service costs $9 per month, while preordering 24 months drops it to $4 a month.
