Densometers are the accepted standard for measuring the porosity of materials such as papers, wovens, plastics and membranes. All Densometers measure the time required for a given volume and of air (25cc to 400cc) to flow through a standard area of material being tested under light uniform pressure. Certain models, such as the S-P-S Tester, are also used to measure surface smoothness and material softness. Manual and automatic units available. Conform to TAPPI T-460, ASTM D-726-58 & APPITA/AS 1301-420, BS 5926, CPPA D-14, ISO 5636/5, D-202-77, SCAN P-19 & P-53.