TST389SO is an AS568-389 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 19.953 in (506.81 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 20.373 in (517.47 mm). In service, this back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
PTFE (Teflon) is specified here for near-universal chemical inertness and non-stick, non-contaminating surface characteristics. The material holds up against nearly all industrial chemicals, strong acids and bases, and oxidizing media. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C).
You will find this material specified across laboratory equipment, pharmaceutical and biotech, and food and beverage.
Stocked as TST389SO and sold individually. Nominal inside diameter is listed as 20 inch. Review your operating media and conditions against this specification before installation.
Description 389 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.21 inch (5.33 mm)
Actual Inside Diameter 19.953 inch (506.81 mm)
Actual Outside Diameter 20.373 inch (517.47 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings