Buna 70-351-Black-Pk5

Part number SB-H70351-5 is an AS568-351 black Buna-N (Nitrile) 70 Shore A O-Ring built to an inside diameter of 4.725 in (120.02 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.145 in (130.68 mm). An o-ring seats in a machined groove and forms a leak-tight barrier when compressed between two mating surfaces. The catalog record notes: 0.210CSX4.725"IDX5.145"OD.

Buna-N (Nitrile) is specified here for economical choice for high-volume maintenance programs, reliable performance in both static and dynamic service. The compound resists propane and butane, hydraulic fluids, and petroleum-based oils. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Exposure to ozone and direct sunlight or polar solvents will shorten service life.

Maintenance and OEM teams specify it across fluid power, hydraulic and pneumatic systems, and general industrial maintenance.

Reference part number SB-H70351-5 when ordering; the item is sold by the bag. Nominal inside diameter is listed as 4 3/4 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation.