Designed to monitor gas concentration in underground parking garages and loading docks, Series GSTC Carbon Monoxide/Nitrogen Dioxide Gas Transmitter is compatible with either BACnet or MODBUS® communication, allowing it to be used with almost any building management controller. Carbon monoxide transmitter measures exhaust of gasoline engines, while nitrogen dioxide transmitter is used for diesel engines. To maximize accuracy, sensor can be field-calibrated using A-449 remote LCD.