Stainless Steel Pipe fittings use a NPT thread to mate male to female pipe thread.
Pipe female swivel or NPSM (National Pipe Straight Mechanical) female steel adapter fittings use a straight parallel thread with a 30° cone seat to mate to a male pipe fitting with a matching chamfer.
SAE J514 37° Degree stainless steel adapter fittings use a 37° flare chamfer to provide an excellent mechanical seal between the male and female adapter
Stainless steel SAE O-Ring Boss (ORB) fittings use a SAE J514 straight thread with an O-ring at the adapter base for a tight seal connection.
O-Ring Face Seal (ORFS) steel adapter fittings are the most recent adapter family designed to provide the ultimate in leak proof protection. These SAE J1453 adapters use an o-ring in the face to create a strong seal.