Provides a cost-effective, easy to install way for installers to comply with building regulations. Simply clips into the flue and connects to the boiler PCB. Suitable for use with horizontal and vertical flue systems up to 4m in length and is compatible with all Baxi combi boilers. Can be used with the Baxi IFOS Extension Kit (available separately) to safely extend the length up to an additional 5m. Sensor housing clips onto the air duct of the flue terminal, kept out of direct sunlight, so no need to fit on a north / north-west wall. Free flow of air over the sensor results in highly accurate temperature sensing, ensuring reliable operation. 2-wire cable runs back to boiler down the flue air duct, no drilling or disruption required. All Baxi Combination Boilers for Horizontal & Vertical Flueing Applications Easy to Install No Drilling Required All Baxi Combination Boilers for Horizontal & Vertical Flueing Applications Easy to Install No Drilling Required