BW-4040, 4″ x 40″ RO Membrane for Desalination of Brackish Water, 99.5% Desalination Rate, 2400 GPD, 2000-5000PPM, BW-4040 Reverse Osmosis Membrane for Groundwater, Municipal, NSF Certified The BW4040 is a 4 inches x 40 inches Reverse Osmosis (RO) membrane element designed for desalination of brackish water. Made of plastic material in a gray color, this membrane is compatible with various brands such as Dow, Samsung Aquarius, Aqua Optima Evolve, and Brita Maxtra+. It is suitable for both commercial and household use, and can effectively remove chemicals from the water. Manufactured by Virego, this RO membrane is a reliable and efficient solution for purifying water in your kitchen or garden.