2103-268 PTFE S/T BUP FDA

Ordered as TST268, this is an AS568-268 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 8.484 in (215.49 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 8.762 in (222.55 mm). The back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

It resists strong acids and bases, nearly all industrial chemicals, and solvents. That behavior comes from the compound itself: PTFE (Teflon) is known for non-stick, non-contaminating surface characteristics and a very wide continuous service temperature range. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. Applications involving service requiring elastic recovery or molten alkali metals call for a different compound.

You will find this material specified across semiconductor fabrication, aggressive-media pipelines, and laboratory equipment.

TST268 ships individually. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.