Personal alarm devices come in different shapes and sizes, but they all have one thing in common: They're designed to give you peace of mind if you ever find yourself in a dangerous situation. They can be used by everyone, from children to the elderly.Using personal alarm devices can help protect your loved ones from violent crimes like murder, assault, and manslaughter, according to the National Institute of Justice. They can also save the lives of older people who may be prone to falls or other in-home accidents.They're loud, easy to use, and make a clear noise when activated—making it hard for an attacker to ignore them. Plus, some models have strobe lights that can draw attention from nearby pedestrians and police.There are keychain and wristband versions of these alarms, as well as ear-piercing models that fit easily on your keys. These aren't as effective as a pendant or backpack model, but they're still pretty useful.They're especially useful for women, kids, the elderly, and teenagers.  man down alarm They're also great for camping, hiking, or any other outdoor activity where you might get lost in the dark. The best of these devices have a siren that's up to 130dB loud, so you can hear it from long distances. They also have LED strobe lights, which are useful for scaring away a potential attacker and getting help. They're also lightweight and easy to carry. They're powered by three AG13/LR44 batteries, which should last for at least 40 minutes on a single charge.