1" NH / NST / NPSH Gasket (5-Pack) Camlock Size_6 inch Two types of threads are

Two types of threads are used:

Metal construction of aluminum

Female 1 inch NPSH

The most common size and threads for US fire hydrants is 2 1/2 inch NH / NST

1" NH / NST / NPSH Gasket (5-Pack) Camlock Size_6 inch Two types of threads areReplacement rubber gaskets are for female couplings or adapters. These gaskets will fit National Hose thread "NH", National Standard Thread "NST" or National Pipe Straight Hose "NPSH". Forest Service Spec 5100 190 National Stock Number 5330 00 720 2621 This Wildland Fire Equipment gasket is used by the U. S. Forest Service (USFS), Bureau of Land Management (BLM), Bureau of Indian Affairs (BIA), U. S. Fish & Wildlife Service (USF&WS), National Park