4MM CS X 78MM ID BLACK BUNA 70D

This o-ring is supplied in black Buna-N (Nitrile) 70 Shore A supplied with an inside diameter of 78 mm (3.071 in), a cross section of 4 mm (0.157 in), and an outside diameter of 86 mm (3.39 in), catalogued under part number H4X78. It provides a reliable static or dynamic seal by deforming into its gland under assembly load.

Buna-N (Nitrile) is widely chosen for an economical choice for high-volume maintenance programs and low compression set under sustained load. Expect good resistance to hydraulic fluids, petroleum-based oils, and greases and lubricants. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C).

Maintenance and OEM teams specify it across fluid power, agricultural equipment, and hydraulic and pneumatic systems.

Reference part number H4X78 when ordering; the item is sold individually. Unit weight is approximately 3.9535 g. Check the compound against your process media, pressure and temperature before committing to a design. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.