568-255 BLACK HNBR HSN70 O-Ring

The HSN70255 is an AS568-255 black HNBR (Hydrogenated Nitrile) 70 Shore A O-Ring built to an inside diameter of 5.609 in (142.47 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.887 in (149.53 mm). This o-ring creates a positive seal at flange, piston and rod interfaces without added hardware.

HNBR (Hydrogenated Nitrile) is specified here for improved ozone and weathering resistance over standard nitrile, oil resistance of nitrile with substantially better heat capability. It resists sour gas and amine inhibitors, petroleum oils and fuels, and heat and oxidation. Published continuous service range is -40°F (-40°C) to 325°F (162.8°C). Applications involving strong oxidizing acids or esters call for a different compound.

Typical settings include heavy-duty powertrain, oilfield and downhole equipment, and engine timing systems.

Reference part number HSN70255 when ordering; the item is sold individually. Unit weight is approximately 5.332 g and nominal inside diameter is listed as 5 5/8 inch. Review your operating media and conditions against this specification before installation. 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.