Abstract: A filter testing device is disclosed wherein the ends of a filter element is clamped between resilient seals in a filter holder member. A dioctyl phthalate smoke generator generates smoke which is passed through the filter element. An annular sampler which is mounted between the top member and base member of the filter holder member is moved vertically along the axial length of the filter. The annular sampler has an annular cavity therein with a plurality of radial holes extending from the inner diameter to the annular cavity. A vacuum pump draws the sample from the annular cavity in the annular sampler into a forward light scattering particulate detector device wherein the quantity of smoke is measured on a meter.