The meter has an inbuilt Lithium battery and a USB charger so can be used as a portable device or remain plugged in all day to continuously monition changing conditions or build up of CO2 etc. if windows left closed all day
Switchable between Centigrade and Fahrenheit with audible alarm setting on/off switch.
Built-in 1800mAh capacity lithium battery, with USB charging cable.
Battery warning flashes to notify when recharging needed
Includes USB Charger