8-043 BLACK BUNA 90D BACK-UP RING

Ordered as HB90043, this is an AS568-043 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 3.489 in (88.62 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 3.629 in (92.18 mm). The back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

As a material, Buna-N (Nitrile) delivers strong abrasion and tear resistance, low compression set under sustained load. Expect good resistance to greases and lubricants, hydraulic fluids, and propane and butane. Published continuous service range is -40°F (-40°C) to 250°F (121.1°C). Verify compatibility before use with ozone and direct sunlight or ketones.

Maintenance and OEM teams specify it across fluid power, agricultural equipment, and automotive.

This item is sold individually under part number HB90043. Unit weight is approximately 0.601 g. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.