Reversible Humidity Indicating Cards

The Reversible Humidity Indicating Cards are a compact, cost-effective solution for monitoring ambient relative humidity (RH) in enclosed environments. Designed with impregnated color-changing spots, these cards visually indicate current humidity levels: from blue (dry) through lavender (moderate) to pink (humid), typically within minutes of exposure. Unlike their maximum/hazard indicators, the color change is reversible—returning to blue as conditions dry—making them reusable for ongoing monitoring. Ideal for use in packaging, storage, archival, fungible packaging, and electronics shipping, these cards provide clear, instant feedback on moisture levels without the need for power or electronic sensors.

Key Features:

Reversible color change: Spots revert from pink back to blue as humidity drops.

Easy-to-read visuals: Intuitive blue–lavender–pink transition indicates moisture levels.

Reusable and passive: No power source required; reliable and low-cost monitoring that can be reused.

Quick response: Color changes typically occur within minutes of exposure to changing RH.

Compact and versatile: Ideal for tight spaces such as display cases, moisture barrier bags, and shipping packages.

Ideal for humidity control: Helps detect environmental moisture intrusion before damage occurs.

Enhanced value: Reusable functionality offers ongoing protection and insight into storage conditions.