8-128 BLACK BUNA 90D BACK-UP RING

HB90128 is an AS568-128 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 1.487 in (37.77 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 1.693 in (43 mm). In service, this back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

Buna-N (Nitrile) is specified for reliable performance in both static and dynamic service, the most widely specified general-purpose sealing elastomer. The material holds up against water, petroleum-based oils, and many alcohols. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). It should not be specified for service in polar solvents or automotive brake fluid.

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

Order part number HB90128, sold individually. Unit weight is approximately 0.471 g. Review your operating media and conditions against this specification before installation.