Plastic 3" NH Cap

Thermoplastic 3 inch NH / NST threaded cap with chain. This cap features a 9 inch chain for a secure connection to the wall or equipment. Constructed from hardened thermoplastic. Chain and gasket included.NOT intended to be pressurized, threaded dust cover only Note - 3 inch NH / NST is very rare and is often confused with 2.5 inch NH / NST which is very common. If you have a fire department connection (FDC), hose coupling or an adapter check the female coupling for stamped numbers and letters. Most 3.0 inch hoses use 2.5 inch NH / NST couplings. The most common fire fitting thread in the United States is 2 1/2 inch NH /NST. If you have two swivel female FDC brass connections that need plugs measure the INSIDE diameter of the swivel fitting. If it measures approximately 3 inches, you need 2 1/2 inch NH / NST plugs. 3 inch NH / NST fittings measure approximately 3 5/8". If you have any doubt it is best to contact your local fire department for size and thread type in your area. If possible it is best to measure the MALE fitting. The outside diameter of a 2.5 inch NH / NST male hose coupling or fire hydrant is 3.06 inches. The outside diameter of a 3.0 inch NH / NST male hose coupling or fire hydrant is 3.62 inches. The outside diameter of a 2.5 inch NPT or NPSH male hose coupling is 2.84 inches. The outside diameter of a 3.0 inch NPT or NPSH male hose coupling is 3.47 inches.