Ordered as TST135, this is an AS568-135 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 1.925 in (48.9 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.131 in (54.13 mm). The back-up ring bridges the extrusion gap so the primary seal holds its shape under load.
As a material, PTFE (Teflon) is widely chosen for near-universal chemical inertness and a very wide continuous service temperature range. The compound resists nearly all industrial chemicals, solvents, and oxidizing media. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). Exposure to elemental fluorine at temperature or molten alkali metals will shorten service life.
Maintenance and OEM teams specify it across food and beverage, aggressive-media pipelines, and pharmaceutical and biotech.
This item is sold individually under part number TST135. Nominal inside diameter is listed as 1 15/16 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.
description 2103-135 PTFE S/T BUP FDA
Actual_CS 0.103 inch (2.62 mm)
Actual_ID 1.925 inch (48.9 mm)
Actual_OD 2.131 inch (54.13 mm)
ProductCode Description O-Rings - Backup Rings