Fort Smart SOS Emergency Button for Smart Alarm System is a quick and easy way to trigger your alarm siren regardless of the current system status at the touch of the button, to protect you and your loved ones. Once paired with your Smart Alarm hub (sold separately), the SOS button will automatically command the hub to dial up to 3 stored emergency phone numbers and sound the built in 95 decibel alarm siren. It fits neatly onto your keys and comes supplied with a battery and is easy to pair with Smart Alarm Hub via radio frequency, with a range of up to 80m (clear line of site) from the hub.