X-Sense CO detector with display incl. 3x AA Battery Carbon monoxide detector - Where do you hang it? In a room with a combustion appliance (possible CO source) On the ceiling - At a horizontal distance between 1 and 3 meters from the CO source - Centrally in the room - At least 30 centimeters from surrounding walls - Not next to air inlets or air outlets or other objects on the ceiling. With a sloping ceiling - At a horizontal distance between 1 and 3 meters from the CO source - Place the detector on the sloping ceiling. In a room without a combustion appliance Bedrooms: at breathing height - At breathing height, the height at which you sleep - Not next to air inlets or air outlets - Not behind objects such as curtains and cupboards. Other areas: at breathing height - Depending on activities in the room, breathing height corresponds to sitting or walking height - Not next to air inlets or air outlets - Not behind objects such as curtains and cupboards.