Part number TST216 is an AS568-216 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 1.109 in (28.17 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 1.387 in (35.23 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.
PTFE (Teflon) is known for non-stick, non-contaminating surface characteristics and one of the lowest coefficients of friction of any solid. The material holds up against strong acids and bases, steam, and oxidizing media. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). Applications involving service requiring elastic recovery or molten alkali metals call for a different compound.
Maintenance and OEM teams specify it across food and beverage, chemical processing, and pharmaceutical and biotech.
Order part number TST216, sold individually. Nominal inside diameter is listed as 1 1/8 inch. Check the compound against your process media, pressure and temperature before committing to a design.
Description 2103-216 PTFE S/T BUP FDA
Actual Cross Section 0.139 inch (3.53 mm)
Actual Inside Diameter 1.109 inch (28.17 mm)
Actual Outside Diameter 1.387 inch (35.23 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings