-040 BLACK BUNA 90D O-RING

The H90040 is an AS568-040 black Buna-N (Nitrile) 90 Shore A O-Ring measuring an inside diameter of 2.864 in (72.75 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 3.004 in (76.3 mm). This o-ring seats in a machined groove and forms a leak-tight barrier when compressed between two mating surfaces.

It resists propane and butane, greases and lubricants, and petroleum-based oils. That behavior comes from the compound itself: Buna-N (Nitrile) is widely chosen for low compression set under sustained load, 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 strong acids or ketones.

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

This item is sold individually under part number H90040. Unit weight is approximately 0.756 g and nominal inside diameter is listed as 2 7/8 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.