SlimTRAK is a covert way to keep valuables under constant surveillance. The 3.6-ounce homing beacon has a GPS transmitter that runs on four AA batteries (should last three months). After you've stuck it on your quarry, just fire up your laptop and head on over to SlimTRAK's site (you'll need a subscription, and yeah, that costs extra) to see a map that updates every five minutes that shows you its exact location. Intended mainly to help recover stolen cars, SlimTRAK can supply the speed, street address, and last stop of a vehicle. However, feel free to stick it onto anything worth keeping an eye on — boat, luggage, nuclear missile — and in the unfortunate event it's stolen, misplaced, or launched, the target's location is only a click away. Priced at $845, SlimTRAK isn't cheap, but for everything truly worth protecting or thwarting, it's an investment in safety.