2103-350 PTFE S/T BUP FDA

APG stocks the TST350, an AS568-350 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 4.6 in (116.84 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.02 in (127.51 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

Expect good resistance to oxidizing media, solvents, and steam. PTFE (Teflon) is widely chosen for a very wide continuous service temperature range and excellent dielectric properties. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). It is not the right choice where elemental fluorine at temperature or molten alkali metals are present.

Maintenance and OEM teams specify it across food and beverage, semiconductor fabrication, and laboratory equipment.

Stocked as TST350 and sold individually. Check the compound against your process media, pressure and temperature before committing to a design. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.