568-128 BUNA 70 SQUARE CUT RINGS

APG stocks the SH70128, an AS568-128 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring built to an inside diameter of 1.487 in (37.77 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 1.693 in (43 mm). A square-cut ring seals with a broad flat contact band instead of the line contact of a round-section ring.

The compound resists water, petroleum-based oils, and greases and lubricants. Buna-N (Nitrile) is widely chosen for an economical choice for high-volume maintenance programs and low compression set under sustained load. 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 strong acids or ketones. The profile itself contributes a flat contact band that spreads sealing load across a wider area 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 automotive, general industrial maintenance, and fluid power.

This item is sold individually under part number SH70128. Unit weight is approximately 0.9979 g. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.