An adapter's whole job is to get from one thread and seal standard to another without opening a leak path in between. It carries two sealing geometries on one body — a 37° cone at one end, a flat O-ring face at the other — and the metal between holds full pressure while the ends take different torques.
The range is large because six connection families are common on US equipment and few machines use one. Across SAE J514, J1453, J1926/ISO 11926, ASME B1.20.1 and ISO 8434-1 there are dozens of sensible combinations, and stocking the adapter beats re-porting the component.
Where it's specified
-
JIC 37° flare — a metal-to-metal cone seat with no elastomer to age, re-sealable after repeated breaking, but unforgiving of over-torque and of a badly formed flare
-
ORFS — a captured O-ring squeezed against a flat machined face, the lowest leak rate under vibration of any threaded joint here, provided groove and face are undamaged
-
SAE ORB against NPT — the two ways into a port: a straight thread pulling an O-ring into the boss chamfer, or a tapered thread wedging on its flanks, which needs sealant and a torque limit
-
NPSM swivels and flareless bite type — answers to hardware already installed: a swivel nut mating a male NPT end on a 30° seat, and a ferrule that bites plain rigid tube, no flaring needed
Range and materials. Zinc-plated carbon steel carries the bulk of the range, with 316/316L stainless alongside for corrosive and washdown service. Shapes run straight, 45°, 90°, tee, cross, bulkhead, swivel and reducer.
Ordering notes. Name both ends in the order the fluid meets them and state gender for each; "1/2 JIC to 1/2 NPT" is ambiguous until you say which is male. A dash number describes the tube or hose an end suits, not its thread, so -08 JIC and -08 ORFS carry different threads. If a joint will be broken often, put the swivel there.
