Humidity indicator card can easily detect the relative humidity in the airtight package. It is a convenient and inexpensive method to detect the humidity in the environment and is safe. The user can quickly judge the ambient temperature inside the product package and the use of desiccant by the change of color on the card. If the temperature in the package reaches, or has ever reached, the point on the card changes from blue to pink. The efficacy of the desiccant can be estimated in order to replace the desiccant in time. Use Weller\'s temperature indicator card to protect your products, especially sophisticated products, from moisture exposure. Humidity indicator card series provides a variety of specifications to choose from, including more commonly used 30-50% temperature indicator and 5-15% humidity indicator, as well as special humidity indicator card for electronic products and independent humidity indicator of 10-60%.