The next layer is an absorption space. This absorbs most of the light entering the collector. It usually consists of an air gap of around 10 cm thickness with one or more absorption meshes suspended vertically in the space. Often window fly screen mesh is used, or horticultural shade cloth. The mesh itself can hold very little heat and warms up rapidly in light. The heat is absorbed by air passing around and through the mesh, and so the mesh is suspended with an air gap on both the front and back sides.