8-019 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90019, an AS568-019 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 0.801 in (20.35 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 0.941 in (23.9 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

The material holds up against petroleum-based oils, many alcohols, and water. That behavior comes from the compound itself: Buna-N (Nitrile) is valued for an economical choice for high-volume maintenance programs and low compression set under sustained load. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service.

Maintenance and OEM teams specify it across fluid power, general industrial maintenance, and automotive.

HB90019 ships individually. Unit weight is approximately 0.154 g. Application requirements vary, so validate compatibility with your process conditions prior to installation.