The polycarbonate membranes are made from high quality polycarbonate films. The pores are obtained using the Track-Etch technique which makes it possible to obtain a well defined pore size and a very good pore distribution on the surface of the membrane. These extremely thin membranes (about 10 µm) are biologically neutral, and have excellent chemical resistance and good thermal stability. Black membranes are also available for testing in fluorescence.