As the humidity increases the chemically impregnated spots change from a blue color (DRY) through a pink, to a lavender color (HUMID). READ AT LAVENDER BETWEEN PINK AND BLUE. As the humidity level decreases the spots change from a lavender color (HUMID) through a pink, to a blue color (DRY). Cards are packaged in re-sealable containers with desiccant for extended shelf life. Each of these cards are accurate to a plus or minus 5 percent relative humidity at 75°F.
Note: These cards have been impregnated with a chemical that may cause corrosion of some metals, therefore we recommend that the card not be placed in direct contact with metal objects. The chemical is no more harmful than table salt to humans.
1 9/16 x 4 3/4 Inch
|Cards per Can||
Top to Bottom 60% Humidity