568-253 BUNA 70 SQUARE CUT RINGS

APG stocks the SH70253, an AS568-253 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring with an inside diameter of 5.359 in (136.12 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.637 in (143.18 mm). A square-cut ring offers greater contact area against the gland wall than an equivalent o-ring.

Buna-N (Nitrile) is valued for reliable performance in both static and dynamic service, the most widely specified general-purpose sealing elastomer. It resists greases and lubricants, hydraulic fluids, and petroleum-based oils. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where ketones or strong acids are present. 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 fluid power, automotive, and construction equipment.

Reference part number SH70253 when ordering; the item is sold individually. Review your operating media and conditions against this specification before installation.