Commonly known as the o ring boss hydraulic fittings(ORB), these types of fittings are defined by the SAE J1926 standard. It defines the dimensions for both the male and female parts. The male part consists of threads given by the Unified Thread Standard with a groove for the placement of an o-ring. The female part has a seat or chamfer from where the threads begin. When the two parts are connected, the rubber-like o-ring compresses between the two seats of the male and female parts. This allows for an extremely tight seal between the two parts, compensating for the dimensional variations. They are commonly manufactured using high-strength carbon or stainless steel to withstand the high-pressure applications they are used in.
SAE ORB fittings are widely available offering a combination of unions, elbows, tee, swivels and bends for use in various applications. The o-ring allows for an extremely tight seal that can withstand high pressures.