2.3Cartridge housing filter parameters inspection Print out the technical drawing of the housing and cross checking one line by one line. Make sure the housing is same as the drawing design. It will include but not limited to: 2.3.1Material identifying We need to check the material of the cartridge filter housing, it means we need to identify the material of parts which are contacted with water/liquid for filtration. Take stainless steel 316 cartridge filter housings as example, the parts for example body, up closure, bottom closure, in/outlets are stainless steel 316 while the davit arm or the legs might be stainless steel 304, unless customers have deliberate requests that all parts need to be stainless steel 316.