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-389 BLACK BUNA 50D O-RING

Buna-N O-Ring, 19.953 in ID x 0.21 CS, 50A, Black, -40 to 250°F

Status
Out of Stock
Est. Ship Date
20 Oct 2026
Material
Buna-N (Nitrile / NBR)
Dash Size
389
Durometer
50 Shore A
Cross Section Type
Round
Color
Black
Minimum Temperature
-40°F (-40°C)
Maximum Temperature
250°F (121°C)
Nominal Cross Section
3/16 inch
Nominal Inside Diameter
20 inch
Nominal Outside Diameter
20 3/8 inch
Unit of Measure
EA
SKU:
H50389

Product Specification

-
Ordered as H50389, this is an AS568-389 black Buna-N (Nitrile) 50 Shore A O-Ring with an inside diameter of 19.953 in (506.81 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 20.373 in (517.47 mm). The o-ring seats in a machined groove and forms a leak-tight barrier when compressed between two mating surfaces.

Buna-N (Nitrile) is specified here for economical choice for high-volume maintenance programs, strong abrasion and tear resistance. The material holds up against greases and lubricants, many alcohols, and petroleum-based oils. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). It is not the right choice where ketones or polar solvents are present.

It sees regular use in construction equipment, automotive, and agricultural equipment.

Stocked as H50389 and sold individually. Nominal inside diameter is listed as 20 inch. Review your operating media and conditions against this specification before installation. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.
Item
H50389
Description
-389 BLACK BUNA 50D O-RING
Actual Cross Section
0.21 inch (5.33 mm)
Actual Inside Diameter
19.953 inch (506.81 mm)
Actual Outside Diameter
20.373 inch (517.47 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6005
Product Category
O-Rings - Bulk - Commodity