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2103-390 PTFE S/T BUP FDA

PTFE Back-Up Ring, 20.953 in ID x 0.21 CS, 55D, White, -65 to 500°F

Status
Out of Stock
Est. Ship Date
21 Oct 2026
Material
PTFE (Polytetrafluoroethylene)
Dash Size
390
Durometer
55 Shore D
Cross Section Type
Round
Color
White
Minimum Temperature
-65°F (-53.9°C)
Maximum Temperature
500°F (260°C)
Nominal Cross Section
3/16 inch
Nominal Inside Diameter
21 inch
Nominal Outside Diameter
21 3/8 inch
Unit of Measure
EA
SKU:
TST390

Product Specification

-
This back-up ring is supplied in AS568-390 white PTFE (Teflon) 55 Shore D built to an inside diameter of 20.953 in (532.21 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 21.373 in (542.87 mm), catalogued under part number TST390. It bridges the extrusion gap so the primary seal holds its shape under load.

PTFE (Teflon) is specified here for non-stick, non-contaminating surface characteristics and near-universal chemical inertness. Expect good resistance to steam, nearly all industrial chemicals, and solvents. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). It should not be specified for service in service requiring elastic recovery or elemental fluorine at temperature.

You will find this material specified across food and beverage, chemical processing, and laboratory equipment.

Reference part number TST390 when ordering; the item is sold individually. Check the compound against your process media, pressure and temperature before committing to a design.
Item
TST390
Description
2103-390 PTFE S/T BUP FDA
Actual Cross Section
0.21 inch (5.33 mm)
Actual Inside Diameter
20.953 inch (532.21 mm)
Actual Outside Diameter
21.373 inch (542.87 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings