The Mace Brand Personal Alarm Keychain is one of our compact personal alarms. The alarm is activated by depressing the button on the front of the alarm but a different button on the back of unit is the only way to deactivate and silence the alarm. - The Mace Brand Personal Alarm Keychain emits a 130dB shriek. - USE: To use the Mace Brand Personal Alarm Keychain simply depress the button on the front of the alarm which will then deter any attacker or intruder but can also function to draw attention to you if you need medical attention or help. To deactivate the alarm depress the button on the back of the alarm. - EXPIRATION: One year after purchasing your Mace Brand Personal Alarm model we recommend you test the alarm to make sure that it is ready to go whenever and wherever.