Flair-It 3/8" PEX Pipe Coupling, is used for hot and cold water plumbing applications. It is made of durable polyoxymethylene (POM) and is compatible with PEX and PB. The patented design consists of a nut and flared insert and requires no tools. The fittings push against the ID and OD of the pipe, creating a strong long-term seal. Valves are directional.