Ordered as TST343SO, this is an AS568-343 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 3.725 in (94.62 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.145 in (105.28 mm). The back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
As a material, PTFE (Teflon) is valued for near-universal chemical inertness and non-stick, non-contaminating surface characteristics. The material holds up against solvents, strong acids and bases, and steam. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). Applications involving molten alkali metals or service requiring elastic recovery call for a different compound.
Maintenance and OEM teams specify it across food and beverage, semiconductor fabrication, and laboratory equipment.
This item is sold individually under part number TST343SO. Nominal inside diameter is listed as 3 3/4 inch. Review your operating media and conditions against this specification before installation.
Description 343 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 3.725 inch (94.62 mm)
Actual Outside Diameter 4.145 inch (105.28 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings