The Permeagraph™ measures gas permeability of porous samples.  Applying differential pressure generated to sample and evaluates permeability from travelling speed of piston.

There is a excellent data correlation with #158 Gurley type Densometer.

This permeability tester is ideal for measuring intermediate range of gas permeability between #571 Gas Transmission Rate Tester and the #158 Gurley type  Densometer.