Humidity indicator card (HIC) is a device on which a moisture-sensitive chemical is impregnated such that it will color change when the indicated relative humidity thresholds exceeded. This has usually been of two types, a blotting paper impregnated with cobalt(II) chloride base and color change blue to pink when RH threshold exceeded; the other is cobalt-free chloride base and color change brown to blue when threshold exceeded.The spots on the humidity indicator card change color to indicate the humidity in a given cargo or environment, allowing workers to monitor humidity at a glance and inspect cargo if humidity exceeds safe levels.Humidity indicator is a cost-effective way to detect and indicate relative humidity levels. They are available in many configurations and used in many applications which sensitive in humidity conditions, especially food, chemicals, military, semiconductor, etc.