1. Thermometer and hygrometer are mechanical structure, no battery needed, easy to use 2. The clock is a quartz watch and needs a button battery to power it 3. Small size, easy to place 4. The notch on the bottom of the thermometer can be opened to adjust the position 5. Purpose: temperature measurement, time, air humidity measurement 6. Measuring temperature: -20 to 70 degrees Celsius 7. Material: steel shell, ABS back cover, glass mirror 8. Size: diameter 4cm 9. Weight: about 42g
