Measures CO? (0 - 9999 ppm), temperature (-10 + 60 °C) and humidity (0,1 - 99,9% RH). CO? precision: ± 50 ppm ± 5% of measurement (0 - 2000 ppm) and ± 10% of the measurement for the other range. Temperature precision: ± 0,6 °C. Humidity precision: ± 3% RH. Ideal for indoor air quality measurement (IAQ). Uses NDIR technology (non dispersive infrarred detector) to ensure long-term reliability and stability. Acoustic alarms, maximum, minimum and average functions. Universal adapter for charging. Warranty 2 years