So are attack alarms (as they call em these days) any use?
We talked to Amanda Howell whose company Sure24 makes some of the attack alarms that the police across the UK hand out to people who want them. According to her, the Police think they're useful for three reasons:
Follow on after the jump
1. Psychological effect. Carrying an attack alarm can make someone look more confident and studies with attackers tend to show that they are more likely to target someone who looks vulnerable.
2. Noise. In the event of an attack, the noise will startle and disorientate the attacker who won't be expecting it. Might also attract attention and help.
3. Time. The shock gives you a few seconds to run.
How do they work?
You push a button or pull a cord and a deafening alarm is unleashed. These range from about 100dB to 150dB.
Things to look for in an attack alarm:
1. Volume: check whether the volume is measured at source or at 1m from the alarm. 140dB is about as loud as a gunshot. Pretty loud.
2. Alarm sound: go for one which sounds different to a car alarm. An article here advises "going for an alarm with a continuous shrill shriek so there is less chance of confusion. If you get a quieter model make sure you go for a very unusual sound."
The Ila Dusk, see review here, supposedly mimics a scream.
3. The Trigger mechanism: has to go off easily in a time of attack, but not too easily. Howell says this was a problem with old ring-pull models that went off accidentally if you were fumbling around in your bag. There should be an easy way to switch it off as well.
4. Size: you should be able to carry it on your person - in a pocket, on a string. If it's too big, you'll put it in your bag and you won't necessarily have time to reach in and find it.
The Elite Alarm
Sure24 claim that their model works well because it's palm-sized, weighs only 30g and is activated by pushing both sides in simultaneously. An action that's easy to do in an emergency but they claim you are unlikely to do by accident. The volume is 120dB at 1m and approx 140dB at source.
See the Elite alarm here.
See also: Samsung's attack-alarm-cum-phone as reviewed by Shiny Shiny.