Industrial & Fire Grade Threaded Aluminum Adapters that meet or exceed NFPA standards 1963.
These adapters are used to change threads, sizes, and styles of fire hose, pipe outlets, fire trucks, hydrants, pumps, industrial systems, and more. Rocker lug styles are common. 
 
Use reducers to connect to a different size fire hoses, or garden hoses to increase the pressure. For example, if your hose is 1.5", connecting a 1" nozzle with a reducer adapter will give you more water pressure.
 
Adapter Terms Guide:
F - Female
M - Male
NH/NST - (National Hose / National Standard Thread) - Both are the same for fire hose threads and are the most common.
NPSH - (National Pipe Straight Hose) Regular straight pipe threads.
GHT - (Garden Hose Thread) - standard garden hose thread. Commonly 3/4".
 
These types of adapters are used by:
U.S. Forest Service (USFS)
Bureau of Land Management (BLM)
Bureau of Indian Affairs (BIA)
U.S. Fish & Wildlife Service (USF&WS)
National Park Service (NPS)
State and Local Governments
Wildland Fire Equipment Agencies
Other Forest Services
Property Owners / Fire Supression
Industrial Application / Dust Control
and more.