8.4MM CS X 399.5MM ID BLACK BUNA 90D

The H90M8.4X399.5 is a black Buna-N (Nitrile) 90 Shore A O-Ring with an inside diameter of 399.5 mm (15.728 in), a cross section of 8.4 mm (0.331 in), and an outside diameter of 416.3 mm (16.39 in). This o-ring delivers dependable bidirectional sealing in a compact groove envelope. Additional detail on this item: Metric O-RING, JIS P400.

Buna-N (Nitrile) is known for strong abrasion and tear resistance, low compression set under sustained load. Expect good resistance to propane and butane, hydraulic fluids, and petroleum-based oils. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where polar solvents or ketones are present.

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

H90M8.4X399.5 ships individually. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.