Continuous CO monitoring with a clear digital display for quick, easy safety checks. Display shows levels in PPM (parts per million). Features cutting edge technology to send fast alerts to allow time to get to safety. The progressive alert differs based on the level of gas concentration. Battery safeguard makes it difficult to fit without batteries in the unit. Easy to install with included twist-and-click mounting bracket. Not suitable for residential properties in Scotland. Please refer to guidance. Standalone AA Alkaline Batteries Supplied 85dBA Alarm at 3m Test/Hush Button Progressive Alert Digital Display Loud Alarm Battery Safeguard Easy to Install Suitable for Use in Rooms Containing a Fuel-Burning Appliance Standalone AA Alkaline Batteries Supplied 85dBA Alarm at 3m Test/Hush Button Progressive Alert Digital Display Loud Alarm Battery Safeguard Easy to Install Suitable for Use in Rooms Containing a Fuel-Burning Appliance