4445-366Y MINNESOTA RUBBER QUAD RING

HQ4445 is an AS568-445 black Buna-N (Nitrile) 70 Shore A Quad-Ring measuring an inside diameter of 7.975 in (202.57 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 8.525 in (216.54 mm). In service, this quad-ring resists spiral failure in reciprocating service thanks to its multi-lobe geometry.

Buna-N (Nitrile) is specified here for low compression set under sustained load and economical choice for high-volume maintenance programs. Expect good resistance to many alcohols, hydraulic fluids, and petroleum-based oils. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Exposure to ketones or automotive brake fluid will shorten service life. The profile itself contributes resistance to the spiral twisting that defeats round-section rings and a parting line located away from the sealing surface.

Maintenance and OEM teams specify it across fluid power, construction equipment, and agricultural equipment.

Reference part number HQ4445 when ordering; the item is sold individually. Nominal inside diameter is listed as 8 inch. Review your operating media and conditions against this specification before installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.