-178 BLACK BUNA 90D O-RING

APG stocks the H90178, an AS568-178 black Buna-N (Nitrile) 90 Shore A O-Ring with an inside diameter of 9.737 in (247.32 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 9.943 in (252.55 mm). An o-ring seats in a machined groove and forms a leak-tight barrier when compressed between two mating surfaces.

Expect good resistance to greases and lubricants, propane and butane, and water. That behavior comes from the compound itself: Buna-N (Nitrile) delivers low compression set under sustained load and an economical choice for high-volume maintenance programs. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). It is not the right choice where ketones or automotive brake fluid are present.

Typical settings include hydraulic and pneumatic systems, automotive, and agricultural equipment.

H90178 ships individually. Unit weight is approximately 5.721 g and nominal inside diameter is listed as 9 3/4 inch. Check the compound against your process media, pressure and temperature before committing to a design. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.