Ordered as HB90207, this is an AS568-207 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 0.546 in (13.87 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 0.824 in (20.93 mm). The back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
The material holds up against many alcohols, water, and hydraulic fluids. Buna-N (Nitrile) is widely chosen for strong abrasion and tear resistance, the most widely specified general-purpose sealing elastomer. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Exposure to strong acids or ketones will shorten service life.
It sees regular use in construction equipment, agricultural equipment, and general industrial maintenance.
Reference part number HB90207 when ordering; the item is sold individually. Unit weight is approximately 0.255 g and nominal inside diameter is listed as 9/16 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.
description 8-207 BLACK BUNA 90D BACK-UP RING
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 0.546 inch (13.87 mm)
Actual_OD 0.824 inch (20.93 )
ProductCode Description O-Rings - Backup Rings