Dow Filmtec TW30-1812-50HR High Rejection Reverse Osmosis Membrane This membrane is rated at 50 Gallons per Day. If you have chlorinated water, we recommend you use a Carbon/Sediment Pre Filter. The residual chlorine in municipal or city water will destroy the Thin Film Composite (TFC) membrane. Dow Filmtec TW30-1812-50HR Reverse Osmosis Membrane elements are for home drinking water. The industry’s most reliable advanced membrane technology and automated fabrication, allow these elements to deliver consistent performance that equipment suppliers, water treatment dealers and residential customers can rely on. This membrane size is 1.75-inch x 11.74-inch and fits in standard size approximately 2-inch x 12-inch pressure vessels. The industry’s most reliable for home drinking water is the Filmtec reverse osmosis membrane elements. Advanced membrane technology and automated fabrication in the Filmtec reverse osmosis membrane allow these elements to deliver consistent performance for all customers. Filmtec reverse osmosis membrane TW30-1812-50HR element is NSF/ANSI Standard 58 listed. Filmtec home drinking water elements are rated at 50 psi and will purify about 20% more water than competitive elements rated at 60 psi. Because of environmental factors actual production may vary.