Buna 70-156-Black-Pk25

The SB-H70156-25 is an AS568-156 black Buna-N (Nitrile) 70 Shore A O-Ring measuring an inside diameter of 4.237 in (107.62 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 4.443 in (112.85 mm). This o-ring seats in a machined groove and forms a leak-tight barrier when compressed between two mating surfaces. Source specification: 4.4375IDX4.25"ODX.0938"CS.

Buna-N (Nitrile) is specified here for economical choice for high-volume maintenance programs, strong abrasion and tear resistance. The compound resists water, petroleum-based oils, and hydraulic fluids. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Exposure to automotive brake fluid or polar solvents will shorten service life.

Maintenance and OEM teams specify it across automotive, construction equipment, and hydraulic and pneumatic systems.

SB-H70156-25 ships by the bag. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.