This instrument is designed to measure the average smoothness, porosity, and softness of paper, paperboard, and films. The test is carried out by determining the time required for a specified volume of air to pass through or over the test specimen under uniform and controlled pressure conditions.

The tester is equipped with an electronic self-starting timer for automatic measurement of air flow through the specimen. The timer starts automatically when the zero mark of the graduated scale passes the reading fork and stops once the predetermined volume of air has passed through the sample, ensuring accurate and repeatable results.