A digital LCD thermometer and hydrometer is great for your room to instantly measure the temperature and relative humidity.
Measures the temperature from -20C to 90C.
Measures the humidity from 10% to 100%.
Uses 2 common LR44/AG13 batteries.
Please check the calibration before using. Please do these 2 steps.
1 – Take small ziplock bag, place a 5-7 drops of water inside. Shake bag. Fill with air and place humidity meter inside. Seal, and place in warm place. Wait 60-120 minutes for the meter to read 99% humidity before removing.
2 – Place 3 tablespoons of regular table salt inside ziplock bag. Add water to salt until the salt is nearly saturated, but water is not free sitting. If to much water present, add a bit more salt. Push salt to one corner of bag, and place the humidity meter on other side. Put bag someplace at room temperature where it can sit undisturbed for the next 48+ hours. The meter should eventually read 75% humidity. Typically these cheap meters register just slightly above or below 75%. If it reads above or below 75%, simply remember the difference and add or subtract that amount from the humidity % reading when you are using the device.