Ordered as H1.78X6.35, this is a black Buna-N (Nitrile) 70 Shore A O-Ring built to an inside diameter of 6.35 mm (0.25 in), a cross section of 1.78 mm (0.07 in), and an outside diameter of 9.91 mm (0.39 in). The o-ring compresses into its gland to block fluid or gas migration across a joint.
The material holds up against petroleum-based oils, propane and butane, and hydraulic fluids. That behavior comes from the compound itself: Buna-N (Nitrile) offers reliable performance in both static and dynamic service, strong abrasion and tear resistance. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). Exposure to polar solvents or strong acids will shorten service life.
It sees regular use in general industrial maintenance, agricultural equipment, and hydraulic and pneumatic systems.
Reference part number H1.78X6.35 when ordering; the item is sold individually. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.
description 1.78MM CS X 6.35MM ID BLACK BUNA 70D
uf_description2 METRIC O-RING
Actual_OD 9.91 mm (0.39 inch)
Actual_CS 1.78 mm (0.07 inch)
Actual_ID 6.35 mm (0.25 inch)
ProductCode Description O-Rings - Metric - Commodity