RO Membrane has good quality,good price ,and good service of ours RO40 membrane housing has the following ... models of 4021, 4040, 4080, 40120, 40160 and so on. They are made of SUS304 or 316.Features ... series 2) 4" membrane housing pipe has two types: seam and seamless 3) The Lid is made of stainless steel 4 ... . It is mainly composed of a filter bag, shell, support rack and