568-251 BUNA 70 SQUARE CUT RINGS

Part number SH70251 is an AS568-251 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring measuring an inside diameter of 5.109 in (129.77 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.387 in (136.83 mm). A square-cut ring offers greater contact area against the gland wall than an equivalent o-ring.

Buna-N (Nitrile) is specified here for most widely specified general-purpose sealing elastomer and low compression set under sustained load. It resists hydraulic fluids, water, and propane and butane. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). The profile itself contributes a flat contact band that spreads sealing load across a wider area and simple lathe-cut manufacture at low tooling cost. Note that a square section is less suited to high-speed rotary service, where the larger contact area raises friction and heat.

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

Order part number SH70251, sold individually. Nominal inside diameter is listed as 5 1/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.