2103-109 PTFE S/T BUP FDA

TST109 is an AS568-109 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 0.299 in (7.59 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 0.505 in (12.83 mm). In service, this 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 known for non-stick, non-contaminating surface characteristics and excellent dielectric properties. This material stands up to nearly all industrial chemicals, solvents, and strong acids and bases. The material carries a published service range of -65°F (-53.9°C) to 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 aggressive-media pipelines, pharmaceutical and biotech, and food and beverage.

This item is sold individually under part number TST109. 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.