APG stocks the TST249SO, an AS568-249 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 4.859 in (123.42 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.137 in (130.48 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
PTFE (Teflon) delivers near-universal chemical inertness and non-stick, non-contaminating surface characteristics. The compound resists nearly all industrial chemicals, solvents, and oxidizing media. The material carries a published service range of -65°F (-53.9°C) to 500°F (260°C). It should not be specified for service in elemental fluorine at temperature or service requiring elastic recovery.
Maintenance and OEM teams specify it across chemical processing, aggressive-media pipelines, and semiconductor fabrication.
TST249SO ships individually. As always, verify media compatibility and operating conditions against the requirements of your specific application.
Description 249 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 4.859 inch (123.42 mm)
Actual Outside Diameter 5.137 inch (130.48 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings