For tube sizes 1/4 inch O. D. Works with copper, cvpc, and PEX pipe permanent leak proof connection easy to install with no tool is required. 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, ultra-filtration 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.