... the CO2 concentration, detecting range 0~20,000 PPM (0~50,000 PPM is optional);• USA Telaire sophisticated NDIR infrared ... performance life of 15 yearsAccuracy±30 PPM+3% reading (For 5°C, 2000 PPM)Stability2%Calibrating PeriodABC Logic automatic calibration ... 10mins (for everyday use)Detecting RangeWall-mounting: 0~2000 PPM, 0~5000 PPM, 0~20000 PPMPipeline type: 0~2000 PPMResolution1 PPMAirflow ...