MXC56789 Maximum and Current Humidity Indicator Card (package of 25 cards) was designed for applications which require monitoring the maximum humidity attained when exposed for a period of 24 hours or more, in addition to the current humidity. Each level of humidity indicated on these cards is represented by a blue crystal which dissolves when the relative humidity (RH) level exceeds the humidity shown below it. When the crystals dissolve, they create a large blue spot above the indicated humidity.  You can also see the current humidity in the bottom section

Example: If the highest humidity level reached is 70% RH, then all circles up to and including 70% will have dissolved crystals and the area surrounding each circle will be stained blue.

Package of 25 cards.