Great self-defense item for any age. The key chain easily attaches to backpacks, purse or car keys. It has a built-in LED light to help in dark/low light areas. In case of emergency simply pull the pin to sound the safety alarm. The alarm is 100 - 110 decibels and can be heard up to 175-225 feet, depending on surrounding conditions. The alarm will quit once the pin is replaced or until the battery dies. Three LR44 replaceable batteries and instructions are included.