Also known as Boss O-rings, these are for use in tube fittings with a straight-thread connection. They're made of hard Buna-N, which is resilient and offers excellent resistance to wear, grease, petroleum fluids, and motor oil. These O-rings have a round profile and are suitable for a wide range of static and dynamic sealing applications. They're sized to the SAE standard AS568.
These O-rings are well suited for most industrial hydraulic and pneumatic systems. They have high extrusion resistance making them suitable for very high pressure static applications. O-rings for other than normal hydraulic media or higher temperature applications can be selected from the following chart.