Non-reversible Cards

These Maximum Humidity Indicator Cards were designed for applications which require monitoring the maximum humidity attained when exposed for a period of 24 hours or more. Each level of humidity indicated on these cards is represented by an orange crystal which dissolves when the RH level exceeds the humidity shown below it. When the crystals dissolve, they create a large yellow spot above the indicated humidity.

This is an inexpensive, simple way to determine if storage or shipping containers have been exposed to high humidity's during their shelf life. The maximum humidity indicator card should not be removed from its waterproof barrier bag until the container in which it is to be placed is ready to be sealed.