*4256-366Y MINNESOTA RUBBER QUAD RING

APG stocks the HQ4256, an AS568-256 black Buna-N (Nitrile) 70 Shore A Quad-Ring with an inside diameter of 5.734 in (145.64 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 6.012 in (152.7 mm). A quad-ring uses a four-lobed profile to create two sealing surfaces per side, reducing the squeeze needed to seal.

Buna-N (Nitrile) delivers low compression set under sustained load, strong abrasion and tear resistance. The material holds up against hydraulic fluids, greases and lubricants, and petroleum-based oils. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. It is not the right choice where ketones or automotive brake fluid are present. The profile itself contributes a parting line located away from the sealing surface and resistance to the spiral twisting that defeats round-section rings.

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

Stocked as HQ4256 and sold individually. Review your operating media and conditions against this specification before installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.