568-389 BUNA 70 SQUARE CUT RINGS

Ordered as SH70389, this is an AS568-389 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring measuring an inside diameter of 19.953 in (506.81 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 20.373 in (517.47 mm). The square-cut ring presents a flat rectangular section that cannot roll or twist in its groove, making it a dependable static seal.

It resists water, petroleum-based oils, and propane and butane. Buna-N (Nitrile) offers strong abrasion and tear resistance, reliable performance in both static and dynamic service. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where ketones or automotive brake fluid are present. The profile itself contributes simple lathe-cut manufacture at low tooling cost and a rectangular section that will not roll in the groove. Note that a square section is less suited to high-speed rotary service, where the larger contact area raises friction and heat.

Maintenance and OEM teams specify it across fluid power, agricultural equipment, and construction equipment.

This item is sold individually under part number SH70389. Application requirements vary, so validate compatibility with your process conditions prior to installation. 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.