Part number TST277 is an AS568-277 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 11.484 in (291.69 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 11.762 in (298.75 mm). A back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.
As a material, PTFE (Teflon) is widely chosen for a very wide continuous service temperature range and non-stick, non-contaminating surface characteristics. The compound resists strong acids and bases, solvents, and oxidizing media. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service.
Maintenance and OEM teams specify it across chemical processing, pharmaceutical and biotech, and food and beverage.
TST277 ships individually. Nominal inside diameter is listed as 11 1/2 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation.
Description 2103-277 PTFE S/T BUP FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 11.484 inch (291.69 mm)
Actual Outside Diameter 11.762 inch (298.75 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings