There are, at present, thousands of manufacturers of personal alarms. Because the technology behind them is relatively simple, there are few barriers to entry in the market. As a consequence, companies that formerly concentrated on other products such as doorbells, telephones, and even flashlights are now veering away from their bread and butter and developing new versions of personal alarms.

Naturally, as more and more players enter the fray, the options that come with these alarms continue to grow. Consumers may now opt for alarms with infrared sensors, colorful housing units, and smaller, more compact designs. Many also boast strong flashing strobe lights for even more visible distress signals. And, of course, the threshold ceiling for decibels continues to rise. Where personal alarms once capped out at just over 100 dB, new models are climbing upwards of 130 dB.

Using Your Personal Alarm

One of the biggest draws of personal alarms is the ease with which they're operated. Many feature little more than a button that, when depressed, emits a screeching, strident wail. But because such designs lend themselves to inadvertent triggering, many feature override buttons that must also be engaged for the horn or siren to sound. Some models require two or three free fingers to operate them.

Another selling point about personal alarms is that, unlike Tasers and fancy home alarm systems, they typically cost no more than a few bucks. Even most mace and pepper spray cans run twice as much (anywhere from 10-15 dollars), though these obviously range widely in price depending on size and potency. Compared with expensive measures, a personal alarm is a tremendous value, providing its user with a proven deterrent for about the cost of an average lunch.