Firstline pressure vessels are engineered for use in Reverse Osmosis systems. 4“ housing is mulpiple lengths: 21", 1-6element Pressure rating is 300psi 450psi 600psi 1000psi and 1200psi Feed/Conentrate port: Side port: 1"side port Victaulic coupling End port: 1/2" or 3/4" FNPT/BSPT Permeate port Side port: 1/2"NPT/BSPT End port: 1/2"NPT/BSPT Perfect option for small-size RO, especially sea-water desalination RO units. Features: Competitive pricing ASME-certified quality Excellent outlook Certificate: ASME and ISO-9001 Manufacturing: Computer-controlled winding machine Curing in specially-designed ovens(most advanced equipment in China) Precision-drilling of side port with proprietary jigs and fixtures Testing: 100% hydraulic tests before delivery Accessories: saddle and strap membrane adaptor Operation conditions: Temperature: -10 ℃ to +66 ℃ Water PH value: 3-11 Product Picture Packaging & Shipping 4"housing is packed into carton, and then onto pallet or plywood box. Packing will be enhanced for international shipping. Our Services Other than pressure housing, we also provide RO membranes, needle vavles, and other components. Company Information We are your Water Partner Shanghai / Florida / Taiwan / South Africa / Nigeria Our sample room: Our warehouse: