Product characteristics: Barometer/hygrometer/thermometer in wooden casing. Pressure measurement range from 960 to 1060 hPa Accuracy of pressure measurement +/- 5 hPa Humidity measurement range form 0 to 100% Accuracy of humidity measurement from +/-3% to +/-5% Temperature measurement range from -20°C to 50°C Error tolerance up to +/-2°C Clock diameter 70 mm Usage: BAROMETER Setting - to set the hand twist the screw at the back of the clock. To set it correctly check the indications in the region of living. Do not hang the thermometer on wet walls or close to heat sources. Before every reading knock softly the glass. You will notice a slight change of pressure level. To obtain better measurement results set the checking hand at the same level as the barometer (so that they cover up) indicator after every reading. HYGROMETER: The main function is to measure the relative humidity of air.