3.5MM CS X 31.7MM ID BLACK BUNA 70D

Ordered as H3.5X31.7, this is a black Buna-N (Nitrile) 70 Shore A O-Ring measuring an inside diameter of 31.7 mm (1.248 in), a cross section of 3.5 mm (0.138 in), and an outside diameter of 38.7 mm (1.52 in). The o-ring compresses into its gland to block fluid or gas migration across a joint. This item is further identified as Metric O-RING, JIS P32.

The compound resists petroleum-based oils, hydraulic fluids, and greases and lubricants. That behavior comes from the compound itself: Buna-N (Nitrile) is known for the most widely specified general-purpose sealing elastomer and low compression set under sustained load. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. It is not the right choice where strong acids or automotive brake fluid are present.

You will find this material specified across automotive, fluid power, and agricultural equipment.

H3.5X31.7 ships individually. Unit weight is approximately 1.3148 g. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.