8-349 BLACK BUNA 90D BACK-UP RING

HB90349 is an AS568-349 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 4.475 in (113.67 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.895 in (124.33 mm). In service, this back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

Buna-N (Nitrile) is specified for reliable performance in both static and dynamic service, strong abrasion and tear resistance. Expect good resistance to propane and butane, greases and lubricants, and petroleum-based oils. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C).

You will find this material specified across hydraulic and pneumatic systems, automotive, and general industrial maintenance.

Order part number HB90349, sold individually. Unit weight is approximately 3.956 g. Application requirements vary, so validate compatibility with your process conditions prior to installation.