Electronic Whistles

For about 10 dollars you can arm yourself with a first-rate signaling device that's handy in emergencies such as natural disasters and criminal activities. Until you've heard the sound that a four-inch-long metal whistle can produce, you may have lingering doubts about its usefulness. Once your ear drums have reverberated to the tune of a 130-decibel siren, however, you can count yourself among the converts.

Despite their relatively crude design, whistles remain popular as personal safety devices. For one thing, they're far more affordable than other deterrents such as Tasers and stun guns, which can often run several hundred dollars. For another, they sport no complex wiring or electrical circuitry and require no formal training to use. As Bacall reminds Bogie in the screen version of Hemingway's To Have and Have Not, "Just put your lips together and blow."

When You Can't Catch Your Breath

High-stress situations can cause the best-laid plans to go astray. That is to say, in the event that you are accosted by potential thieves or sexual predators, your alert whistle may not be easily accessible. This is one reason why many people carry their whistles on their key chains. It's also a reason why safety products developers came up with button-based whistles that are much easier to sound in a real crisis.

Most of these devices come with safety switches that allow you to disable their alert capabilities, which is a good idea if you're in a movie theater, concert hall, or art gallery. At the same time, you want to be sure to re-activate your handheld whistle as soon as you've left the venue. This can generally be done merely by flipping a switch or pressing a second button that's somewhat removed from the primary signaler, just to prevent inadvertent activation.