Carbon Monoxide(CO) Detector SPD200/CO Measurement display: displays with 4 digit LCD Operation temperature:-10~50ºC (14~122°F) Storing temperature: 0~40ºC(32~104°C) Operation humidity: 0~99%RH (relative humidity) Storing humidity: 20%~80% RH (relative humidity) Measuring range: 0~1000PPM Resolution: 1PPM Measurement error: ±5% Over measurement range display: --OL-- Alarming method: acousto-optic alarming Working principle of the sensor: electrochemistry sensor The service life of the sensor: 2 years (it can be then replaced) Power supply: 3×1.5V AAA alkaline batteries Battery service life: about 100 hours of continuous use (when the backlight is off). Size: 172×51×26 (mm)