Exposed Area: 25 cm²
Dimensions: 8.1 x 2.5 cm (3.25 x 1 in)
During a test, vapor passes from the cup through the film specimen to an open container of desiccant or other absorbent material in a controlled environment. The permeability cup and other container are sealed together in a larger container to provide control of the vapor pressure. Testing may also be set up to allow passage of vapor from a solution in the open container through the test film to a desiccant or other absorbent material within the permeability cup.