Flair-It 1/2" CUx1/2" CU Transition Fitting. Made from durable polyoxymethylene (POM), this fitting is compatible with PEX and PB. Its patented design features a nut and flared insert, requiring no tools for easy installation. Suitable for copper, PEX, polybutylene, or CPVC tubing, the fittings push against the ID and OD of the pipe, creating a strong long-term seal.