This is the key component of the iSpring residential and light commercial reverse osmosis water purification system, usually used in the 4th stage. It has very tiny holes, which allow only water and a few gases to pass through under certain pressure thus produces virtually pure water. The technology has been used in spaceships to recycle water for astronauts. It is effective in reducing hardness, heavy metals, toxins, free chlorine, bad taste, odor THM, organics, hazardous chemicals, and pesticide. Depending on inlet water quality and usage, it needs to be replaced every 24 months or 2600 gallons of water. State-of-the-art Dual-Flow 500GPD membrane enables full contact of water with the membranes. Increases water production by 15%, while reducing waste water by 60%, more environmental safe with a 1:1 drain to clean water ratio. Why iSpring Located in Alpharetta, Georgia for over a decade, iSpring water systems LLC is a family owned company specializing in reverse osmosis water filtration systems. Our products include residential and commercial reverse osmosis (ro) systems, whole house water systems, ultrafiltration systems, shower, faucet, and counter top filters, filter cartridges and housings, RO coolers, and kitchen faucets and fittings. Our aim is to make high quality drinking water accessible for all households. With affordable pricing, solid quality, prompt delivery, and top notch customer service, we hope to assist in bringing you great water for years to come.