2103-345 PTFE S/T BUP FDA

APG stocks the TST345, an AS568-345 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 3.975 in (100.97 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.395 in (111.63 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

As a material, PTFE (Teflon) is specified for one of the lowest coefficients of friction of any solid and non-stick, non-contaminating surface characteristics. Expect good resistance to solvents, nearly all industrial chemicals, and strong acids and bases. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). Applications involving elemental fluorine at temperature or molten alkali metals call for a different compound.

Maintenance and OEM teams specify it across food and beverage, chemical processing, and laboratory equipment.

This item is sold individually under part number TST345. Check the compound against your process media, pressure and temperature before committing to a design. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.