This Humidity Indicator Card is a color-change indicator and is reversible. As the humidity increases, the chemically impregnated spots change from a blue color (DRY), through a lavender, to a pink color (HUMID). As the humidity decreases, the spots change from a pink color (HUMID), through a lavender, back to a blue color (DRY).
Each of these cards is accurate to ±5% relative humidity (RH) at 75°F (24°C). Other humidity combinations are available by special order.
NOTE: This card has been impregnated with a chemical that may cause corrosion of some metals; therefore, AGM recommends that the card not be placed in direct contact with metal objects.