Keensen Technology Co.,ltd which is the manufacturer of RO and NF membrane . the membrane flat sheet technology is import from USA . Residential: 50,75,100,200,300,400 GPD with NF and RO series . Industrial : Brackish Water Membrane,Fouling Resistant Membrane, Ultra-low Pressure Membrane,Extra-low Pressure Membrane,Purpose Industrial Membrane,ect .(8040,4040,4021,2540 )