5.7MM CS X 249.3MM ID BLACK BUNA 70D

The H5.7X249.3 is a black Buna-N (Nitrile) 70 Shore A O-Ring with an inside diameter of 249.3 mm (9.815 in), a cross section of 5.7 mm (0.224 in), and an outside diameter of 260.7 mm (10.26 in). This o-ring compresses into its gland to block fluid or gas migration across a joint. Source specification: Metric O-RING, JIS G250.

Expect good resistance to greases and lubricants, hydraulic fluids, and propane and butane. That behavior comes from the compound itself: Buna-N (Nitrile) is widely chosen for an economical choice for high-volume maintenance programs, strong abrasion and tear resistance. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Applications involving polar solvents or ketones call for a different compound.

Maintenance and OEM teams specify it across automotive, general industrial maintenance, and hydraulic and pneumatic systems.

Reference part number H5.7X249.3 when ordering; the item is sold individually. Unit weight is approximately 24.667 g. As always, verify media compatibility and operating conditions against the requirements of your specific application. 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.