Stainless Steel Lock Nut - Compatible with 1/2" NPT fittings
This hex locknut is a stainless steel cast pipe fitting with female National Pipe Taper (NPT) threads for locking two fittings into place for stability and reduced vibrations. The locknut has NPT threads for creating tighter seals than straight threads. The hexagonal shape provides increased leverage for use with a wrench during installation and disassembly.
This lock nut is not grooved. For the grooved version that seats a silicone compression O-ring see here: