Telaire T1552 Outside Air Enclosure is a rugged weatherproof enclosure (ABS plastic), designed to allow the Telaire T8000 Series 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 approximately 30 minutes to measure a 90% step change in concentrations. Enclosure is designed to screw directly to a wall. Compatible with all Telaire T8000 Series Models (T8100, T8200, T8300). (CO2 sensor not included.)