Humiditity Indicator Card

A humidity indicator card (HIC) is a small, usually paper-based card used to monitor relative humidity levels inside sealed environments like packaging, storage containers, or electronic enclosures. What it looks like Typically a rectangular card with colored spots or circles Each spot corresponds to a specific humidity level (e.g., 10%, 20%, 30%, up to 90%) The spots change color depending on moisture exposure How it works The card is coated with moisture-sensitive chemicals (often cobalt chloride or safer alternatives) When humidity rises above a certain level, the indicator spots change color (commonly from blue → pink or brown → green depending on type) When humidity drops, some cards may revert back (reversible types), while others remain changed (irreversible types) Common uses Packaging for electronics (to prevent moisture damage) Storage of pharmaceuticals Military and aerospace equipment Optical instruments and cameras Moisture-sensitive components like semiconductors Why it's important Excess humidity can cause: Corrosion Mold growth Electrical failures Humidity indicator cards provide a quick visual check so users know whether the environment has stayed within safe humidity limits.