PEX x Male Threaded Adapter allows for a straight transition between PEX tubing and a threaded fitting. Threaded side is Male NPT thread. These crimp style brass PEX fittings are compatible with crimp or clamp connection systems. Size (Male Threaded Adapter) : - 3/8" PEX x 1/2" - 1/2" PEX x 1/2" - 1/2" PEX x 3/4" - 5/8" PEX x 1/2" - 3/4" PEX x