LOW COST PORTABLE METER CHECKING POOR INDOOR AIR QUALITY IN OFFICE_x000D_ DUAL DISPLAY 2 PARAMETERS SIMULATNEOUSLY:CO2, TEMPERATURE_x000D_ WARNING CARBON DIOXIDE LEVEL_x000D_ BIG LCD DISPLAY WITH HIGH RESOLUTION_x000D_ DESIGN WITH NDIR (Non-Dispersive Infrared) WAVEGUIDE TECHNOLOGY SENSOR_x000D_ MANUAL CALIBRATION IS RECOMMENDED