348 SOLID PTFE BACKUP RING FDA

PTFE Back-Up Ring, 4.35 in ID x 0.21 CS, 55D, White, -65 to 500°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
PTFE (Polytetrafluoroethylene)
Dash Size
348
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 3/8 inch
Nominal Outside Diameter
4 3/4 inch
Unit of Measure
EA
SKU:
TST348SO
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Product Specification

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This back-up ring is supplied in AS568-348 white PTFE (Teflon) 55 Shore D measuring an inside diameter of 4.35 in (110.49 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.77 in (121.16 mm), catalogued under part number TST348SO. It extends o-ring service life by supporting the seal against extrusion under high pressure.

PTFE (Teflon) is specified here for near-universal chemical inertness and one of the lowest coefficients of friction of any solid. The material holds up against steam, strong acids and bases, and oxidizing media. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). Applications involving service requiring elastic recovery or molten alkali metals call for a different compound.

Typical settings include aggressive-media pipelines, food and beverage, and chemical processing.

Stocked as TST348SO and sold individually. Check the compound against your process media, pressure and temperature before committing to a design. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.
Item
TST348SO
Description
348 SOLID PTFE BACKUP RING FDA
Actual Cross Section
0.21 inch (5.33 mm)
Actual Inside Diameter
4.35 inch (110.49 mm)
Actual Outside Diameter
4.77 inch (121.16 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings