This portable weather station is composed of a barometer, a thermometer and a hygrometer Measures barometric pressure (hPa), temperature (C) and humidity ( percent RH) With metric system. Its superiorities include simplicity, reliability and easy reading No special maintenance work is necessary during its long term use This Dial type weather station is made of superior materials Specification: Product Diameter 132mm (5.2") Product Thickness 38mm (1.5") Relative humidity 20 percent - 45 percent RH , 9 percent RH Relative humidity 45 percent - 75 percent RH , 6 percent RH Relative humidity 75 percent - 98 percent RH , 9 percent RH Barometric pressure 1060hPa - 1030hPa , 10hPa Barometric pressure 1030hPa - 990hPa , 5hPa Barometric pressure 990hPa - 960hPa , 10hPa Temperature -20C - 50C , 2C Technical Index No special maintenance work is necessary during its long term use. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.