The XIKAR PuroTemp Wireless Hygrometer System requires no calibration and can read up to 3 separate remote units in different locations/humidors within a 60 foot range. This digital hygrometer allows you to read the temperature and humidity level inside your humidor without having to open it! This is the device that you need to avoid the dramatic fluctuations that can ruin your precious cigars! Make cigar collecting a stress-free activity with the XIKAR PuroTemp Wireless Hygrometer System. You can set up a high/low alarm to alert you when the humidor is not at the desired humidty level. This kit contains one base unit and one remote sensor to be placed inside the humidor. Additional remote sensors for use in multiple locations/humidors are sold separately. Accuracy has been tested to +-2% humidity and 1 degree Celsius. Features a 12/24 hour clock.