Used to extract small invertebrate animals from a dry soil sample. The sample is placed in a container with a base made from gauze with a mesh designed to hold soil particles but permit the animals to pass. The container is arranged over a funnel - with a light above. The heat causes the animals to move away from the top of the sample - through the gauze sheet and into the funnel from which they can be collected. Most species are collected after two hours - but complete extraction takes two-three days.