The AK-Series, family of proprietary thin-film reverse osmosis membrane elements are characterized by high flux and excellent sodium chloride rejection. AK Low Pressure Brackish Water Elements are selected when high rejection and low operating pressures are desired. These elements allow significant energy savings since good rejection is achieved at operating pressures as low as 100 psig (689 kPa). AK4040FM Low Pressure Brackish Water elements feature a tape outerwrap and 28 mil feed spacers. This element is designed with male end connections.