Part number HB90205 is an AS568-205 black Buna-N (Nitrile) 90 Shore A Back-Up Ring supplied with an inside diameter of 0.421 in (10.69 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 0.699 in (17.75 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
Buna-N (Nitrile) is specified here for low compression set under sustained load, reliable performance in both static and dynamic service. This material stands up to propane and butane, petroleum-based oils, and water. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Verify compatibility before use with ozone and direct sunlight or automotive brake fluid.
You will find this material specified across construction equipment, hydraulic and pneumatic systems, and automotive.
Order part number HB90205, sold individually. Unit weight is approximately 0.2135 g. As always, verify media compatibility and operating conditions against the requirements of your specific application. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.
description 8-205 BLACK BUNA 90D BACK-UP RING
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 0.421 inch (10.69 mm)
Actual_OD 0.699 inch (17.75 )
ProductCode Description O-Rings - Backup Rings