Buna 70-344-Black-Pk25

The SB-H70344-25 is an AS568-344 black Buna-N (Nitrile) 70 Shore A O-Ring measuring an inside diameter of 3.85 in (97.79 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.27 in (108.46 mm). This o-ring provides a reliable static or dynamic seal by deforming into its gland under assembly load. This item is further identified as 4.25IDX3.875"ODX.1875"CS.

Expect good resistance to propane and butane, water, and petroleum-based oils. That behavior comes from the compound itself: Buna-N (Nitrile) is specified for low compression set under sustained load and an economical choice for high-volume maintenance programs. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Verify compatibility before use with ozone and direct sunlight or polar solvents.

Maintenance and OEM teams specify it across fluid power, general industrial maintenance, and automotive.

SB-H70344-25 ships by the bag. Nominal inside diameter is listed as 3 7/8 inch. Check the compound against your process media, pressure and temperature before committing to a design. For a size or compound outside the standard catalog, APG can quote from a print or sample.