4MM CS X 39MM ID BLACK BUNA 70D

Ordered as H4X39, this is a black Buna-N (Nitrile) 70 Shore A O-Ring measuring an inside diameter of 39 mm (1.535 in), a cross section of 4 mm (0.157 in), and an outside diameter of 47 mm (1.85 in). The o-ring seats in a machined groove and forms a leak-tight barrier when compressed between two mating surfaces.

Buna-N (Nitrile) is specified here for low compression set under sustained load and economical choice for high-volume maintenance programs. It resists petroleum-based oils, greases and lubricants, and hydraulic fluids. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where polar solvents or ketones are present.

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

This item is sold individually under part number H4X39. Unit weight is approximately 2.124 g. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.