Change of filter-cassette from paper to metal is mandatory,5FSE702590-27 DMI250-280,5FSE702590-27 DMI250-280,AIR-AIR-cooler, AIR-WATER cooler,AIR-AIR-cooler, AIR-WATER cooler,require 2 pcs/cooler, size 880x400x50,require 2 pcs/cooler, size 880x400x50