SINPO SPO201 Palm Size Type Oxygen(O2 ) Alarm Detector Measuring 0~25％ VOL w/ LCD Backllight Features: Use the imported Oxygen sensor, high accuracy and stable performance. Adopt Intellectualized design,to realise multi functions. High LCD backllight display, acousto-optic alarm, easy to operate. The in-built temperature compensation makes the meter measure accurately from ﹣10℃  to 40℃.    The ergonomicalcase design provides an exquisite apperance, good texture and convenience.                                                                                 Specifications: Model: Oxygen Gas Alarm Detector SPD201/O2                                           Measurement display: displays 4 digit LCD Operation temperature: -10~40C (14~104F) Storing temperature: 0~30C (32~86F) Operation humidity: 0~99%RH (relative humidity) Storing humidity: 20%~80% RH (relative humidity) Measuring range: 0~25%(VOL) Resolution: 0.1 %( VOL) Measurement tolerance: +/-0.5% Over measurement range display: --OL-- Alarming method: acousto-optic alarming Working principle of the sensor: Source battery sensor The service life of the sensor: 2 years (it can then be replaced) Power supply: 3 * 1.5V AAA alkaline batteries(not included) Battery service life: about 100 hours of continuous use (when the backlight is off). Product Size: 172 * 51 * 26 (mm)    Package Size: 26 * 17 * 6cm / 10 * 7 * 2.3in Package Weight: 488g / 1.1lb Package List:                                                                         1 * SINPO SPO201 Oxygen(O2 ) Alarm Detector 1 * Carrying Bag 1 * English Manual