Personal Attack Alarms:
There are two main types of Personal Attack or Screech Alarm as they are sometimes called. Both are designed to do the same job, distract an assailant giving you time to react and to draw attention to you and your plight.
The first is the gas operated one, this is the Alarm with the green top in the picture below. Gas operated alarms work by attaching a whistle – the green cap – to a bottle of liquid propellant, much the same way as aerosols function. When the cap is depressed the propellant is forced up through the whistle via a thin tube. The propellant evaporates once it makes contact with the air and so drive through the whistle at a very high speed, this produces the familiar screeching sound form which this type of alarm draws its name.
The second alarm. The small black and silver box with a cord attached to it, is battery operated. The box contains a battery and a small speaker and siren. When the cord is pulled it releases a pin that allows a circuit inside the alarm to be completed, the siren is activated and the alarm sounds. Both Alarms will produce a sound of up to 140 Decibels. This is quite loud. Especially in a confined space or if the alarm is triggered near an assailants head. Lets look at each alarm in turn.
Gas operated
Very light and cheap –hence their popularity. Average running time approximately 20 minutes. Average Decibel output 140 Decibels. Gas operated alarms do suffer from some disadvantages. We advise women to activate their alarm and throw it on the ground, gas operated alarms have a tendency for the top to come off when impacting on a hard surface. This renders the alarm ineffective.
They are not very versatile and sometimes can be activated accidentally if in a handbag. We have also known these alarms to leak, the propellant evaporates and the alarm is useless. If you have one of these alarms you should agitate the propellant regularly by shaking the bottle and ensure the nozzle of the top is clean.
Dirt in the nozzle can prevent the alarm from functioning correctly. Once a gas operated alarms propellant is expended the alarm is useless; there are no refills available.
Battery operated
Slightly heavier than the gas-operated alarms and a little more expensive. Average running time at least 30 minutes. Average Decibel output 140 Decibels.
Powered by a small battery these alarms are far more versatile and we recommend them as Self Defence Aids to all our students. Due to their design, they fit nicely in the hand and make a good improvised and legal striking weapon. Constructed of very strong plastic, they survive being dropped or thrown to the floor and keep on working. The pull cord usually has a clip at the other end from the pin; this allows the alarm to be placed in a handbag with the cord attached to the person. If the bag is snatched the alarm is activated. The thief then has a wailing handbag! Some alarms come supplied with an attachment for a door, enabling them to be used as an emergency intruder alarm for a hotel room for example.
Some battery-operated alarms are now fitted with a mini strobe light also allowing them to be seen as well as heard, making them doubly effective.
The cost of these Alarms can range from £5 - £7 for a gas operated one and between £7 - £10 for a battery operated one. They can be found cheaper if you shop around.