Most commonly used at point of use fixtures, it allows for repair and maintenance of fixtures without the need to shut down flow control to the entire system. The 1/4 in. compression outlet provides the capability to install 1/4 in. O.D. tubing or 1/4 in. supply lines. It is designed for use on point of use fixtures such as refrigerators, ice makers and water filtration devices. Apollo Expansion Pex barb fittings are a key component to one of the most economical potable water piping systems.