The GE Desal AK4021TF Dry - Filmtec Style reverse osmosis elements are used for brackish water desalination.The Desal AK4021TF RO element is tape wrapped.The A-Series thin-film reverse osmosis membrane elements are characterized by high flux and excellent sodium chloride rejection.GE Osmonics Desal AK4021TF High Rejection Brackish Water reverse osmosis elements feature a tape outer wrap and 28 mil feed spacers and is designed with male end connections.GE Desal AK High Rejection Brackish Water Elements are selected when high rejection and operating pressures as low as 100 psig are desired.