We have John Guest 3/8"Stem X 1/4" Quick Connect Fittings. Quick connect fittings have push-fit technology which makes installation and disconnection very easy, without the need of tools. Just fit the tubing into the quick connection end and push in passed the connection opening. These parts are food grade quality and should only be used with liquids and reverse osmosis water systems. These connections work with soft metal and plastic tubes. Do no use with gas, compressed air, or vacuums. They have superior water flow characteristics.