Part number SH70125 is an AS568-125 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring measuring an inside diameter of 1.299 in (32.99 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 1.505 in (38.23 mm). A square-cut ring resists the spiral failure that affects round rings on long reciprocating strokes.
Expect good resistance to propane and butane, water, and petroleum-based oils. That behavior comes from the compound itself: Buna-N (Nitrile) delivers reliable performance in both static and dynamic service, low compression set under sustained load. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Applications involving ketones or automotive brake fluid call for a different compound. The profile itself contributes greater resistance to extrusion than a round section of the same size 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.
Maintenance and OEM teams specify it across hydraulic and pneumatic systems, agricultural equipment, and construction equipment.
Reference part number SH70125 when ordering; the item is sold individually. Unit weight is approximately 0.5724 g. As always, verify media compatibility and operating conditions against the requirements of your specific application. For a size or compound outside the standard catalog, APG can quote from a print or sample.
description 568-125 BUNA 70 SQUARE CUT RINGS
Actual_CS 0.103 inch (2.62 mm)
Actual_ID 1.299 inch (32.99 mm)
Actual_OD 1.505 inch (38.23 mm)
ProductCode Description O-Rings - Square/Quad - Commodity