340 PTFE SOLID BACKUP RING FDA

The TST340SO is an AS568-340 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 3.35 in (85.09 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 3.77 in (95.76 mm). This back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

It resists solvents, oxidizing media, and strong acids and bases. That behavior comes from the compound itself: PTFE (Teflon) is widely chosen for non-stick, non-contaminating surface characteristics and a very wide continuous service temperature range. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C).

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

This item is sold individually under part number TST340SO. Nominal inside diameter is listed as 3 3/8 inch. Check the compound against your process media, pressure and temperature before committing to a design. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.