Ordered as H5.7X399.3, this is a black Buna-N (Nitrile) 70 Shore A O-Ring measuring an inside diameter of 399.3 mm (15.72 in), a cross section of 5.7 mm (0.224 in), and an outside diameter of 410.7 mm (16.17 in). The o-ring remains the most cost-effective sealing element available for pressurized assemblies. The catalog record notes: Metric O-RING, JIS G400.
The compound resists water, petroleum-based oils, and hydraulic fluids. Buna-N (Nitrile) is widely chosen for strong abrasion and tear resistance, the most widely specified general-purpose sealing elastomer. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). It should not be specified for service in automotive brake fluid or polar solvents.
You will find this material specified across general industrial maintenance, construction equipment, and fluid power.
Order part number H5.7X399.3, sold individually. Review your operating media and conditions against this specification before installation.
Description 5.7MM CS X 399.3MM ID BLACK BUNA 70D
Actual Outside Diameter 410.7 mm (16.17 inch)
Actual Cross Section 5.7 mm (0.224 inch)
Actual Inside Diameter 399.3 mm (15.72 inch)
Measurement System Metric
Product Category O-Rings - Metric - Commodity