8-435 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90435, an AS568-435 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 5.725 in (145.42 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 6.275 in (159.39 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

Expect good resistance to greases and lubricants, petroleum-based oils, and propane and butane. That behavior comes from the compound itself: Buna-N (Nitrile) offers the most widely specified general-purpose sealing elastomer, strong abrasion and tear resistance. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). Verify compatibility before use with ketones or ozone and direct sunlight.

It sees regular use in construction equipment, fluid power, and general industrial maintenance.

HB90435 ships individually. Unit weight is approximately 9.93 g. As always, verify media compatibility and operating conditions against the requirements of your specific application.