Question: are all pex fittings the same?
Answer: All expansion fittings can be divided into (2) major groups: ... Expansion style fittings can be used only with PEX-A tubing and are not compatible with other PEX tubing types. Compression PEX-AL-PEX Fittings. Unlike most other methods, PEX-AL-PEX connection method does not require a PEX tool.