This weather station is a so-called bi-metal thermometer and bi-metal hygrometer. Certain tolerable deviations from one another and from digital weather stations, for example, are normal and can be found in the item description. The advantage of bimetal measuring devices is that they do not contain any liquid substances and you do not need any batteries. That protects the environment. At the same time it is a cheaper option for weather measurement. Product details: 14 cm, height approx. 4 cm, weight 180gStainless steel frame, dial made of aluminum, cover made of sturdy plastic glassFor mounting on the wall, mounting material includedUsable outside and insideBarometer measuring range 960 to 1060 hPa, accuracy +/- 5hPaThermometer measuring range -20 to 50 C, accuracy +/- 2 CHygrometer measuring range 20 to 98% RH, accuracy at 45 - 75% RH +/- 6%