4 Spot Humidity Indicator Card P/N: 4HIC100 Designed for dry packaging Surface Mount Devices. Monitors the most critical humidity range for SMD’s. Color reference bar assists with accurate readings. Humidity Indicator Cards (HIC’s) are printed with moisture sensitive spots which respond to various levels of humidity with a visible color change from blue to pink. HIC's are placed inside vacuum sealed (dry packed) moisture barrier bags. When the bag is opened, the card can be examined for proper dryness inside the bag.