4.5MM CS X 31.5MM ID BLACK BUNA 70D

APG stocks the H4.5X31.5, a black Buna-N (Nitrile) 70 Shore A O-Ring measuring an inside diameter of 31.5 mm (1.24 in), a cross section of 4.5 mm (0.177 in), and an outside diameter of 40.5 mm (1.59 in). An o-ring remains the most cost-effective sealing element available for pressurized assemblies.

It resists water, many alcohols, and propane and butane. That behavior comes from the compound itself: Buna-N (Nitrile) is widely chosen for reliable performance in both static and dynamic service, the most widely specified general-purpose sealing elastomer. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C).

Maintenance and OEM teams specify it across hydraulic and pneumatic systems, fluid power, and general industrial maintenance.

This item is sold individually under part number H4.5X31.5. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. For a size or compound outside the standard catalog, APG can quote from a print or sample.