2103-348 PTFE S/T BUP FDA

The TST348 is an AS568-348 white PTFE (Teflon) 55 Shore D Back-Up Ring supplied with an inside diameter of 4.35 in (110.49 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.77 in (121.16 mm). 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 excellent dielectric properties and non-stick, non-contaminating surface characteristics. The material holds up against nearly all industrial chemicals, strong acids and bases, and oxidizing media. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). It is not the right choice where service requiring elastic recovery or elemental fluorine at temperature are present.

Maintenance and OEM teams specify it across pharmaceutical and biotech, laboratory equipment, and food and beverage.

This item is sold individually under part number TST348. 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.