This CO alarm is part of the Visit smart home system that helps you to secure your home. It discovers dangerous concentrations of carbon monoxide early and relays the alarm directly to your Visit receiver, so you can get out of harm's way in time. Type: Electrochemical Features Battery - Long lasting power up to 5 years battery life. Hush Function - To avoid nuisance alarms. Broadcast Feature - Relays the alarm to all receivers Reliable Connection - Up to 160 m operating range. In the box CO Alarm Bracket Screws