-257 BLACK BUNA 90D O-RING

This o-ring is supplied in AS568-257 black Buna-N (Nitrile) 90 Shore A built to an inside diameter of 5.859 in (148.82 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 6.137 in (155.88 mm), catalogued under part number H90257. It creates a positive seal at flange, piston and rod interfaces without added hardware.

The compound resists greases and lubricants, hydraulic fluids, and propane and butane. Buna-N (Nitrile) delivers low compression set under sustained load, reliable performance in both static and dynamic service. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Verify compatibility before use with polar solvents or ketones.

It sees regular use in construction equipment, hydraulic and pneumatic systems, and automotive.

Reference part number H90257 when ordering; the item is sold individually. Unit weight is approximately 6.3303 g. Check the compound against your process media, pressure and temperature before committing to a design. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.