Ordered as H90M1.78X8.75, this is a black Buna-N (Nitrile) 90 Shore A O-Ring with an inside diameter of 8.75 mm (0.344 in), a cross section of 1.78 mm (0.07 in), and an outside diameter of 12.31 mm (0.48 in). The o-ring seats in a machined groove and forms a leak-tight barrier when compressed between two mating surfaces.
As a material, Buna-N (Nitrile) is valued for reliable performance in both static and dynamic service, the most widely specified general-purpose sealing elastomer. The compound resists greases and lubricants, propane and butane, and many alcohols. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Applications involving strong acids or ketones call for a different compound.
Typical settings include automotive, construction equipment, and agricultural equipment.
Reference part number H90M1.78X8.75 when ordering; the item is sold individually. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.
Description 1.78MM CS X 8.75MM ID BLACK BUNA 90D
Actual Outside Diameter 12.31 mm (0.48 inch)
Actual Cross Section 1.78 mm (0.07 inch)
Actual Inside Diameter 8.75 mm (0.344 inch)
Measurement System Metric
Product Category O-Rings - Metric - Commodity