APG stocks the HB90346, an AS568-346 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 4.1 in (104.14 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.52 in (114.81 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
As a material, Buna-N (Nitrile) offers reliable performance in both static and dynamic service, an economical choice for high-volume maintenance programs. It resists many alcohols, petroleum-based oils, and propane and butane. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C).
Typical settings include automotive, general industrial maintenance, and agricultural equipment.
This item is sold individually under part number HB90346. Unit weight is approximately 3.6 g. 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.
Description 8-346 BLACK BUNA 90D BACK-UP RING
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 4.1 inch (104.14 mm)
Actual Outside Diameter 4.52 inch (114.81 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings