Part number H90251 is an AS568-251 black Buna-N (Nitrile) 90 Shore A O-Ring supplied with 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). An o-ring remains the most cost-effective sealing element available for pressurized assemblies.
Buna-N (Nitrile) is specified for low compression set under sustained load, strong abrasion and tear resistance. It resists propane and butane, petroleum-based oils, and water. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). Applications involving ketones or ozone and direct sunlight call for a different compound.
You will find this material specified across fluid power, general industrial maintenance, and automotive.
Order part number H90251, sold individually. Unit weight is approximately 5.387 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 -251 BLACK BUNA 90D O-RING
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 5.109 inch (129.77 mm)
Actual Outside Diameter 5.387 inch (136.83 mm)
Measurement System Imperial
Product Category O-Rings - Bulk - Commodity