The Telaire T1551Outside Air Enclosure for T8000 Series is a rugged weatherproof enclosure (ABS plastic), designed to allow the 8000 series sensor to operate in an outdoor environment and/or where ambient temperatures are below freezing. The 1551 is ideal for monitoring outside air or CO2 as a surrogate for combustion fumes in parking garages, tunnels and loading docks. This enclosure features a temperature control circuit and internal heaters to maintain the sensor within its normal operating temperature range, even if temperatures outside the enclosure are as low as –20° F (-29° C). Four diffusion ports allow for entry of CO2. Response time of the sensor is slowed to approximately 30 minutes to measure a 90% step change in concentrations. Enclosure is designed to screw directly to a wall. CO2 sensor is not included.