VIEGA Rotguss Coupling 1/2″ Female x Female Thread, Gunmetal (Brass Alloy), Art. 266585

Both ends of the coupling are female, so it needs male-threaded parts: a 1/2" pipe or nipple screwed in from each side. To join two female-threaded parts instead, you need a nipple with male threads at both ends rather than a coupling.

The threads are Rp to DIN EN 10226-1, parallel female threads that seal against the tapered R thread of the pipe. Use hemp with sealing paste, PTFE thread tape or thread-sealing cord. The paste keeps the hemp from drying out, makes screwing in easier and fills any gaps left in the thread.

For threaded joints, Viega names a fine-tooth metal saw blade, a wire brush, a pipe wrench or open-ended spanner, and a sanitary cross key. The polygonal body of this coupling is made for a spanner, so you can hold it while you tighten the pipe and keep it from turning.