On the road, your smartphone is a lifeline. Lose it, and you're dead. A crop of new products promises to help make sure that doesn't happen. On a recent trip, I tested a few. I brought my iPhone 4S and my Motorola RAZR MAXX Android phone-and did my best to lose them.

First, I checked out the plastic Cobra Tag ($80). About the size of a thumb drive, it works with a free app for Android and BlackBerry phones and the iPhone. After pairing the tag with your phone, you select a warning-alarm distance-either 10 feet or 30 feet away-to arm it. Sure enough, when a colleague snuck away with my RAZR, the Cobra Tag stashed in my bag made a whoo-whoo-whoo! loud enough for me to hear, without alerting airport security. (If you leave your phone somewhere, the app will send an e-mail or text telling you where you last had it.)

The Tag can't help if someone takes your phone and keeps walking, though. So I downloaded a free app called Lookout to my iPhone and registered with my e-mail address. (Lookout also works with Android phones and iPads.) This time, my colleague took my iPhone to a secret location in another part of the airport. I logged in to the Lookout website on my laptop (you can use a mobile device, too), and within five minutes, I had a map with my phone's location. I transmitted a "scream" from my laptop to the phone, which made my colleague (and everyone around her) jump. As she came back to meet me, I could track her movements by refreshing the map in my browser. The premium version of Lookout ($29.99 a year) also lets you lock or remotely delete data from your phone if it's stolen. (Apple's free Find My iPhone app also does this.)

Of course, most of us don't think about installing an app like Lookout until it's too late. For us, there's Plan B, a free app for Android phones only. After leaving my phone with my colleague, I took a stroll to a different concourse in the airport, opened my laptop, and downloaded Plan B from the Google Play app store. Plan B installs to your phone remotely, enabling GPS tracking whenever the phone is turned on. Within seconds, I got an e-mail saying my phone had been found. Five minutes later, I had a map showing me where to find it. I shut my laptop and crept up silently on my colleague. (Plan B doesn't have a "scream" option.)

I'm going to keep Cobra Tag, because in addition to guarding my phone, it can help me find it in my cluttered office. (Tapping a button on the Tag will sound an alarm on your phone.) I'm glad to have Lookout on my iPhone, and I plan to put it on my Android phone, too. But if I forget-entirely possible-it's great to know I've got a viable Plan B.


Protect it with...Cobra Tag ($80)

Find it with...Lookout (free; premium version, $29.99 a year) or Plan B (free)


Protect it with...Cobra Tag

Find it with...Lookout or Find My iPhone (free)