No battery required (operates on bimetal strip) Record the max-min temperature Anti-rain structure design and can be hung in the outdoor use 2 in 1 Thermometer Hygrometer 2 Units: Celsius and Fahrenheit, Celsius / Fahrenheit<br><br>Temperature Measuring range: - 20 ~ 50 Celsius / 0-120Fahrenheit Humidity Measuring range 0 ~ 100% Resolution Resolution: 1Celsius, 2% Accuracy of measurement Accuracy, plus or minus 2 Fahrenheit + / - 5%, (40% ~ 70%) Product Size Unite the Size: 128mm / 5inches Colour:Golden Material:metal Size:Diameter: 128mm<br><br>Package Contents: 1 x Humidity Meter<br><br>Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.