568-428 BUNA 70 SQUARE CUT RINGS

APG stocks the SH70428, an AS568-428 black Buna-N (Nitrile) 70 Shore A square profile Quad-Ring with an inside diameter of 4.85 in (123.19 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 5.4 in (137.16 mm). A quad-ring delivers lower friction and better sealing stability than a comparable round-section o-ring.

The compound resists water, greases and lubricants, and hydraulic fluids. That behavior comes from the compound itself: Buna-N (Nitrile) is specified for low compression set under sustained load, strong abrasion and tear resistance. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where polar solvents or ozone and direct sunlight are present.

It sees regular use in fluid power, automotive, and hydraulic and pneumatic systems.

Reference part number SH70428 when ordering; the item is sold individually. Nominal inside diameter is listed as 4 7/8 inch. 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.