**349 PTFE SOLID BACKUP RING FDA

PTFE Back-Up Ring, 4.475 in ID x 0.21 CS, 55D, White, -65 to 500°F

Status
Out of Stock
Est. Ship Date
29 Oct 2026
Material
PTFE (Polytetrafluoroethylene)
Dash Size
349
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
4 1/2 inch
Nominal Outside Diameter
4 7/8 inch
Unit of Measure
EA
SKU:
TST349SO

Product Specification

-
This back-up ring is supplied in AS568-349 white PTFE (Teflon) 55 Shore D supplied with an inside diameter of 4.475 in (113.67 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.895 in (124.33 mm), catalogued under part number TST349SO. It bridges the extrusion gap so the primary seal holds its shape under load.

It resists strong acids and bases, steam, and solvents. PTFE (Teflon) is valued for a very wide continuous service temperature range and one of the lowest coefficients of friction of any solid. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. Exposure to molten alkali metals or elemental fluorine at temperature will shorten service life.

Typical settings include food and beverage, pharmaceutical and biotech, and semiconductor fabrication.

TST349SO ships individually. Nominal inside diameter is listed as 4 1/2 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.
Item
TST349SO
Description
**349 PTFE SOLID BACKUP RING FDA
Actual Cross Section
0.21 inch (5.33 mm)
Actual Inside Diameter
4.475 inch (113.67 mm)
Actual Outside Diameter
4.895 inch (124.33 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings