5.7MM CS X 239.3MM ID BLACK BUNA 90D

Ordered as H90M5.7X239.3, this is a black Buna-N (Nitrile) 90 Shore A O-Ring supplied with an inside diameter of 239.3 mm (9.421 in), a cross section of 5.7 mm (0.224 in), and an outside diameter of 250.7 mm (9.87 in). The o-ring remains the most cost-effective sealing element available for pressurized assemblies. The catalog record notes: Metric O-RING, JIS G240.

It resists many alcohols, hydraulic fluids, and petroleum-based oils. That behavior comes from the compound itself: Buna-N (Nitrile) offers strong abrasion and tear resistance, an economical choice for high-volume maintenance programs. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). Verify compatibility before use with polar solvents or ozone and direct sunlight.

Maintenance and OEM teams specify it across agricultural equipment, general industrial maintenance, and automotive.

Order part number H90M5.7X239.3, sold individually. Check the compound against your process media, pressure and temperature before committing to a design. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.