The ear thermometer is a device capable of achieving infra-red temperature measurement when placed in the auditory canal of a subject. It is a safe means of measuring human body temperature through the ear. Soft operation keys not to disturb a sleeping baby. If you have no operation within one minute, it will shut off automatically. Measurement temperature range: from 32.0 to 42.9 degrees Celsius Display L when temperature is under 32 degrees Celsius Display H when temperature is over 42.9 degrees Celsius Operating ambient: ( temperature ) from 16 to 35 degrees Celsius Long term storage range: ( temperature ) from -10 to 55 degrees Celsius 10 temperature memories automatically stored for easy recall Fast response only needs one second for measuring Unlimited usage times Long life endurance Using 1.5V AAA battery (not included)