XIKAR Digital Hygrometers have been redesigned to ensure accuracy right out of the box, without having to calibrate. You now have more time to spend enjoying your cigars, not caring for them! XIKAR hygrometers are manufactured to our exact specifications for long term accuracy and minimal maintenance. They accurately display the relative humidity and temperature in your humidor. Meter has a refresh rate of 10 seconds. Uses one LR1130 button cell battery (included).