2103-203 PTFE S/T BUP FDA

The TST203 is an AS568-203 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 0.296 in (7.52 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 0.574 in (14.58 mm). This back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

This material stands up to strong acids and bases, steam, and nearly all industrial chemicals. That behavior comes from the compound itself: PTFE (Teflon) is known for excellent dielectric properties and near-universal chemical inertness. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service.

Typical settings include semiconductor fabrication, chemical processing, and laboratory equipment.

Reference part number TST203 when ordering; the item is sold individually. Nominal inside diameter is listed as 5/16 inch. 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.