Review on Goabroa 12 Pack Mini Small Hygrometer Thermometer: Digital Indoor Humidity Gauge Monitor with Temperature Meter Sensor (℉) – Bulk Pack for Accurate Climate Control by Henry Johnston

Bought these for extra humidity/temperature reading for my cigar humidors. Liked the size and simplicity. They all read differently out of the box. This is to be expected as it is 12 pcs. Basic hygrometer that must be checked for accuracy as standard and marked for calibration. How: Take a bottle cap. Fill it with table salt. Add a few drops of water (do not fill above the salt line - not a mush). Place the hygrometers and lid in an airtight container or good ziplock bag for 24 hours. Note the 75% error of each hygrometer. After completing all but 1 (which I won't use) they were only rejected by 1-2%. 11/12 units at their known nominal discrepancy and less than $20. Its worth it. Buy it with confidence. Note: This seller came with a handwritten note. Nice gesture.