This o-ring is supplied in AS568-278 black Buna-N (Nitrile) 50 Shore A built to an inside diameter of 11.984 in (304.39 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 12.262 in (311.45 mm), catalogued under part number H50278. It creates a positive seal at flange, piston and rod interfaces without added hardware.
As a material, Buna-N (Nitrile) offers an economical choice for high-volume maintenance programs and low compression set under sustained load. It resists water, many alcohols, and petroleum-based oils. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service.
Maintenance and OEM teams specify it across hydraulic and pneumatic systems, agricultural equipment, and general industrial maintenance.
H50278 ships individually. Nominal inside diameter is listed as 12 inch. Review your operating media and conditions against this specification before installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.
Description -278 BLACK BUNA 50D O-RING
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 11.984 inch (304.39 mm)
Actual Outside Diameter 12.262 inch (311.45 mm)
Measurement System Imperial
Product Category O-Rings - Bulk - Commodity