The SCS 4HIC100 Humidity Card, 4-Spot, 100/Can measures the level of relative humidity that the contents of the packaging have been exposed to. For use in combination with moisture barrier bags and desiccant to provide complete protection for moisture sensitive items such as surface mount devices. When the bag is opened, the card can be examined for proper dryness inside the bag. The moisture sensitive spots are made of blotting paper imbued with cobaltous chloride.