These relative humidity cards easily indicate the presence of moisture in the air when their color changes from blue to pink. The cards can be reused. Just place the cards in a dry environment until they return to blue.

The cards are ideal for use in conjunction with the compartment desiccator, mini-dehumidifier, and desiccant bags. Place the cards in a desiccating chamber to indicate the relative humidity within the chamber. Two types of cards are available.

The 30% RH card changes color when the moisture content rises to 30% RH. The 10-60% RH card has 6 spots corresponding to 10, 20, 30, 40, 50, and 60% RH that change color individually when the moisture content reaches the indicated level.