Designed to draw attention to any crisis, our self defense PAL-1 130db Personal Alarm is as loud as eight 100db alarms. The self defense alarm is activated when the strap attached to the alarm pin is pulled. Travels easily on your belt or in your purse. The Door Alarm accessory converts the Personal Alarm into a portable door or window alarm. Great for home, hotel rooms, college dorms, etc. Use 9-volt battery (not included).