4 " or 8" membrane housing with different pressure and length for Ro water treatment system. Features: 1) Side port2) FRP twisted case 3) Thread connection at fresh water outlet: 1/2" female thread4) Working pressure: 300 or 1,000psi5) Internal diameter: 101mm6) Available lengths: 1, 2, 3, 4, 5 or 6 cores (the numbers of membrane element)7) Operating temperature: -7°C ~ 49°C