568-250 BUNA 70 SQUARE CUT RINGS

SH70250 is an AS568-250 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring with an inside diameter of 4.984 in (126.59 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.262 in (133.65 mm). In service, this square-cut ring seals with a broad flat contact band instead of the line contact of a round-section ring.

It resists water, many alcohols, and petroleum-based oils. That behavior comes from the compound itself: Buna-N (Nitrile) delivers reliable performance in both static and dynamic service, the most widely specified general-purpose sealing elastomer. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). It should not be specified for service in automotive brake fluid or ozone and direct sunlight. The profile itself contributes a rectangular section that will not roll in the groove and greater resistance to extrusion than a round section of the same size. 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, hydraulic and pneumatic systems, and agricultural equipment.

Reference part number SH70250 when ordering; the item is sold individually. Unit weight is approximately 5.8871 g. Check the compound against your process media, pressure and temperature before committing to a design.