-343 BLACK BUNA 70D O-RING

Ordered as H70MD343, this is an AS568-343 black Buna-N (Nitrile) 70 Shore A O-Ring measuring an inside diameter of 3.725 in (94.62 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.145 in (105.28 mm). The o-ring seats in a machined groove and forms a leak-tight barrier when compressed between two mating surfaces.

The material holds up against greases and lubricants, propane and butane, and many alcohols. That behavior comes from the compound itself: Buna-N (Nitrile) is specified for the most widely specified general-purpose sealing elastomer, reliable performance in both static and dynamic service. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where ozone and direct sunlight or polar solvents are present.

The compound is metal detectable for HACCP and foreign-body control programs. Maintenance and OEM teams specify it across hydraulic and pneumatic systems, automotive, and fluid power.

Order part number H70MD343, sold individually. Nominal inside diameter is listed as 3 3/4 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.