The pass box in the clean room is primarily used for the transfer of small items between the non-clean area and clean area, the clean areas of different grade, in order to reduce the number of clean room door and minimize the denuded zone pollution. Pass box are widely used in micro-technologies, biological laboratories, pharmaceutical plants, hospitals, food processing industries, LCDs, electronics factories, and other places where purified air is needed.

Generally the pass box is made of stainless steel. But when the corrosive material is transferred, the stainless steel may not be able to withstand the corrosion. In this case, the polypropylene pass box would be a better choice as it can resist most of the corrosive materials.