Product can replace the return air column and 100-thick hollow shrapnel wall in the small room (changing clothes, removing shoes and cushioning room). The return air module is processed in the factory and assembled on site just like ourmanual board, which is convenient and quiock to installn the later stage, according to customer requirements, the product iseasy to clean and the air volume is adjustable. Advantage: 1. Hollow air return wall can replace clean room air return column and save clean room space. 2. Drilling with international advanced technology, beautiful and generous. 3. Factory prefabrication, site splicing, convenient and quick installation. 4. The strength, flatness and aesthetics of hollow return wall board are greatly improved. 5. Install flush with cleanroom wall panel.