4MM CS X 129MM ID BLACK BUNA 70D

Ordered as H4X129, this is a black Buna-N (Nitrile) 70 Shore A O-Ring built to an inside diameter of 129 mm (5.079 in), a cross section of 4 mm (0.157 in), and an outside diameter of 137 mm (5.39 in). The o-ring provides a reliable static or dynamic seal by deforming into its gland under assembly load.

It resists many alcohols, petroleum-based oils, and greases and lubricants. That behavior comes from the compound itself: Buna-N (Nitrile) is known for reliable performance in both static and dynamic service, an economical choice for high-volume maintenance programs. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service.

You will find this material specified across agricultural equipment, fluid power, and hydraulic and pneumatic systems.

Stocked as H4X129 and sold individually. Unit weight is approximately 6.412 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.