Humidity indicator cards (HICs) are printed with moisture sensitive spots which respond to various levels of humidity with a visible colour change from blue to pink.

• Accuracy based on ambient temperature of 75 °F
• Tolerance is approximately 2,5% for each 10 °F away from 75 °F

The moisture sensitive spots are made of blotting paper impregnated with cobaltous chloride. The humidity inside dry packed barrier bags can be monitored by including an HIC inside. When the bag is opened, the card can be examined for proper dryness inside the bag.

4-spot is designed for dry packaging SMD's, colour reference bar assists with accurate readings. 6-spot is used in a variety of dry packaging application, this card monitors humidity levels across the widest range. 3-spot is popular for military applications.