8-218 BLACK BUNA 90D BACK-UP RING

The HB90218 is an AS568-218 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 1.234 in (31.34 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 1.512 in (38.4 mm). This back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

Buna-N (Nitrile) offers the most widely specified general-purpose sealing elastomer, reliable performance in both static and dynamic service. The material holds up against many alcohols, hydraulic fluids, and greases and lubricants. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Verify compatibility before use with automotive brake fluid or ozone and direct sunlight.

Typical settings include general industrial maintenance, construction equipment, and fluid power.

Order part number HB90218, sold individually. Unit weight is approximately 0.4884 g and nominal inside diameter is listed as 1 1/4 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.