... it suitable for the clean room which is keel type.2. The integrative flange is made of galvanized steel and have many ... options for diameter:250, 300,3503. The HEPA filter is ... . The efficiency for production: H10, H11, H12, H13, H14,U15.U16,U17.(EN1822-4,5) The HEPA filter box in knock-down type