These are used as a replacement for damaged hammer union nuts on one-piece flange adapters. They are made from forged steel and meet AISI standards. They can be installed on pre-existing hammer union assemblies and are interchangeable with other reliable brands. Cold working pressure 2000psi. Note: It is recommended to use Loctite 243 threadlocker when bolting two-piece nuts together to ensure bolts don't lossen when in service. Alternatively, these nuts can be welded together. Bolt torque rating 60ft/lbs.