This round digital hygrometer is the same size as standard analog hygrometers that typically come in humidors. Replace your current analog hygrometer with this digital hygrometer for more accurate and easy humidity readings. This hygrometer will not need to be recalibrated as often as an analog. Accurate to +/- 2% at 70% humidity. Registers temperature in Fahrenheit and Celsius. Fully adjustable one-step push button calibration. Instructions enclosed. Dimensions: 1.75 in. diameter