Buna 70-249-Black-Pk10

This o-ring is supplied in AS568-249 black Buna-N (Nitrile) 70 Shore A supplied with an inside diameter of 4.859 in (123.42 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.137 in (130.48 mm), catalogued under part number SB-H70249-10. It provides a reliable static or dynamic seal by deforming into its gland under assembly load. The catalog record notes: 5.125IDX4.875"ODX.125"CS.

Expect good resistance to water, many alcohols, and hydraulic fluids. That behavior comes from the compound itself: Buna-N (Nitrile) is known for low compression set under sustained load and an economical choice for high-volume maintenance programs. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). It should not be specified for service in polar solvents or strong acids.

Maintenance and OEM teams specify it across fluid power, automotive, and hydraulic and pneumatic systems.

Order part number SB-H70249-10, sold by the bag. Check the compound against your process media, pressure and temperature before committing to a design. For a size or compound outside the standard catalog, APG can quote from a print or sample.