Hexagonal Nipple Available in ½", ¾", 1", 1¼", 1½" and 2" This black malleable iron hexagonal nipple is used to join two threaded fittings while allowing easy tightening with a spanner thanks to its hex centre. Strong, compact, and practical, it’s perfect for structural pipe furniture and decorative pipework. Common uses: Extending pipe runs, joining fittings in tight spaces, furniture frames.