I used to be a certified instructor for the Refuse To Be A Victim crime prevention seminar, and I would be happy to address the personal alarm question.

A personal alarm is an battery operated device that emits a shriek or siren when activated. Some are louder and/or more piercing than others. Some are absolutely earsplitting.

Personal alarms are recommended by safety experts and crime prevention seminars for attracting attention when in trouble of some kind, such as when you are approached or harrassed by unsavory characters. A couple of advantages of these alarms is that they can sound an alarm even if you are unable to, such as if you have been hit or punched in the mouth, or are unconscious, and they are much louder than any whistle. The disadvantage is that, while the alarm will sound for quite some time, the battery will eventually run down.

I am sure that someone could make the argument that with all of the car alarms going off when they shouldn't, that no one will pay attention to the sound of a personal alarm. However, that sound does get your attention, and that alone can send an attacker on the run. One thing attackers don't want is attention. Between the shriek of the alarm and cries for help, others are bound to know that someone is in trouble.

In a situation other than personal attack, the decision of whether to use a whistle or personal alarm is mainly one of personal preference. One just needs to weigh the advantages and disadvantages of each device.

If you are interested in a personal alarm, there are many types and styles available. Some are about the size of a pack of cigarettes that can be worn in a pocket, clipped to a belt, carried in a purse, etc. Many of these are triggered when a lanyard is pulled. Some look like a small dumbbell that you just carry in your hand and activate by squeezing. They are great for walkers and joggers.

Personal alarms do not need to be expensive. You can get a pretty good one at Radio Shack for about $15, if memory serves. You just have to shop around and see what is available. I bought a pretty sophisticated one at a garage sale for about $2.00 one time.

If you do consider buying one, you should either try it out first, or make sure that you can return it later if it isn't what you expected. Before activating it for the first time, be sure to read the instructions and learn how to shut it off (trust me).