Features:1) Wall mounting and duct type2) carbon dioxide detection and temperature and humidity detection optional3) American GE/Telaire NDIR infrared CO2 module is internal with the wide detectionrange4) Self-calibration system makes CO2 sensor usage without calibration with 15-yearlifetime 5) Providing one/two/three analog output: 0~5V DC/0~10V DC or 4~20mA 6) One relay output is available7) RS-485 communication interface is optional: 15KV antistatic protection, independentaddress setting 8) Optional 6 lights indicate CO2 level: 2 x green + 2 x yellow + 2 x red lights9) Wall mounting type and duct type selectable producing area:China payment:T/T