This is most useful on reverse osmosis units, water filtration systems, pneumatics and food / beverage dispensers where multiple connections are necessary. This fitting is fully approved by various safety organisations including NSF, ANSI, WRAS and SK Zert. These are produced from high quality materials that can work in conjunction with semi-rigid plastics (polypropylene, polyethylene, nylon), softer metals (brass, mild steel, copper) and tubing. Flexible tubing will require soft tube supports, available at an extra cost.