3MM CS X 300MM ID BLACK BUNA 70D

Part number H3X300 is a black Buna-N (Nitrile) 70 Shore A O-Ring supplied with an inside diameter of 300 mm (11.811 in), a cross section of 3 mm (0.118 in), and an outside diameter of 306 mm (12.05 in). An o-ring seats in a machined groove and forms a leak-tight barrier when compressed between two mating surfaces.

Expect good resistance to many alcohols, propane and butane, and greases and lubricants. That behavior comes from the compound itself: Buna-N (Nitrile) is specified for the most widely specified general-purpose sealing elastomer and low compression set under sustained load. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Exposure to polar solvents or ketones will shorten service life.

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

This item is sold individually under part number H3X300. Unit weight is approximately 8.308 g. 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.