4MM CS X 255MM ID BLACK BUNA 70D

The H4X255 is a black Buna-N (Nitrile) 70 Shore A O-Ring built to an inside diameter of 255 mm (10.039 in), a cross section of 4 mm (0.157 in), and an outside diameter of 263 mm (10.35 in). This o-ring remains the most cost-effective sealing element available for pressurized assemblies.

This material stands up to many alcohols, propane and butane, and water. That behavior comes from the compound itself: Buna-N (Nitrile) offers low compression set under sustained load, reliable performance in both static and dynamic service. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). Applications involving ketones or strong acids call for a different compound.

You will find this material specified across general industrial maintenance, hydraulic and pneumatic systems, and fluid power.

Reference part number H4X255 when ordering; the item is sold individually. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.