4378-366Y MINNESOTA RUBBER QUAD RING

Part number HQ4378 is an AS568-378 black Buna-N (Nitrile) 70 Shore A quad profile Quad-Ring with 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.

Buna-N (Nitrile) is specified here for economical choice for high-volume maintenance programs, reliable performance in both static and dynamic service. The material holds up against petroleum-based oils, greases and lubricants, and many alcohols. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Verify compatibility before use with ozone and direct sunlight or automotive brake fluid.

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

Reference part number HQ4378 when ordering; the item is sold individually. Check the compound against your process media, pressure and temperature before committing to a design.