Description Features Indoor and outdoor temperature display thermometer Indoor and outdoor humidity display hygrometer Indoor temperature range: -9.9~ 59.9C; outdoor temperature range:-39.9~ 69.9C Temperature accuracy /-1.5C under working temperature 0-50C, resolution 0.1C Relative humidity range: 20%~95%, resolution 1% Records max/min temperature and humidity (indoor and outdoor) Comfort level indicator Low battery indicator Time display in 12/24h White backlight will lit for a few seconds after you press light button on top Main unit can be matched up to 3 remote sensors (one is included. Extras are currently unavailable) The CH button on screen is for switching channels. Postion Method: table standing or wall hanging Main unit: powered by 3xAAA batteries (not included) Remote Sensor: powered by 2xAAA batteries (not included) Battery Life: 12 months