2103-235 PTFE S/T BUP FDA

APG stocks the TST235, an AS568-235 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 3.109 in (78.97 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 3.387 in (86.03 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) offers non-stick, non-contaminating surface characteristics and near-universal chemical inertness. The compound resists steam, strong acids and bases, and nearly all industrial chemicals. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. It should not be specified for service in molten alkali metals or elemental fluorine at temperature.

Maintenance and OEM teams specify it across laboratory equipment, aggressive-media pipelines, and pharmaceutical and biotech.

This item is sold individually under part number TST235. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.