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.Rectangular Hygrometer Features:•Measures 2"L x 3.25"W x .375"D •Accurate to +/- 2% at 70% humidity •Reads humidity in the range of 20% to 95% •Registers temperature in Fahrenheit and Celsius •One step calibration button. Push and hold for 5 seconds and unit self-calibrates. •Min/ Max feature displays lowest minimum and highest maximum humidity recorded over the life of the battery or until reset. •Low battery indicator.