568-039 BUNA 70 SQUARE CUT RINGS

APG stocks the SH70039, an AS568-039 black Buna-N (Nitrile) 70 Shore A square profile Quad-Ring with an inside diameter of 2.739 in (69.57 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 2.879 in (73.13 mm). A quad-ring uses a four-lobed profile to create two sealing surfaces per side, reducing the squeeze needed to seal.

Expect good resistance to hydraulic fluids, many alcohols, and greases and lubricants. That behavior comes from the compound itself: Buna-N (Nitrile) is valued 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). Exposure to polar solvents or automotive brake fluid will shorten service life.

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

This item is sold individually under part number SH70039. Unit weight is approximately 0.786 g and nominal inside diameter is listed as 2 3/4 inch. Review your operating media and conditions against this specification before installation.