2103-387 PTFE S/T BUP FDA

TST387 is an AS568-387 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 17.955 in (456.06 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 18.375 in (466.73 mm). In service, this back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

The compound resists oxidizing media, steam, and nearly all industrial chemicals. That behavior comes from the compound itself: PTFE (Teflon) offers excellent dielectric properties and one of the lowest coefficients of friction of any solid. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C). It should not be specified for service in elemental fluorine at temperature or service requiring elastic recovery.

Maintenance and OEM teams specify it across pharmaceutical and biotech, laboratory equipment, and chemical processing.

Reference part number TST387 when ordering; the item is sold individually. Nominal inside diameter is listed as 18 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing.