The Flec Cell (Field and Laboratory Emission Cell) is made of certified solid acid-resisting stainless steel. All surfaces, getting in touch with the sample emitted, are polished. This provides, together with the very small surface area of the test-chamber, a dramatic minimizing of the sink-effect compared to the sinkeffect of conventional chambers. The outlet split provides up to 90% of the supplied air to be collected on one or two sample tubes, and secure a very small, but constant overpressure in the chamber.