Q-378 BUNA 70 Q RING

Part number QH70378 is an AS568-378 black Buna-N (Nitrile) 70 Shore A Quad-Ring measuring an inside diameter of 10.475 in (266.07 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 10.895 in (276.73 mm). A quad-ring delivers lower friction and better sealing stability than a comparable round-section o-ring.

It resists petroleum-based oils, propane and butane, and many alcohols. 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. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Verify compatibility before use with strong acids or ketones. The profile itself contributes resistance to the spiral twisting that defeats round-section rings and two sealing bands per contact face rather than one.

Common environments for this compound include automotive, fluid power, and agricultural equipment.

QH70378 ships individually. Nominal inside diameter is listed as 10 1/2 inch. Check the compound against your process media, pressure and temperature before committing to a design. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.