2103-439 PTFE S/T BUP FDA

This back-up ring is supplied in AS568-439 white PTFE (Teflon) 55 Shore D with an inside diameter of 6.475 in (164.47 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 7.025 in (178.44 mm), catalogued under part number TST439. It bridges the extrusion gap so the primary seal holds its shape under load.

The material holds up against strong acids and bases, nearly all industrial chemicals, and steam. PTFE (Teflon) is specified for a very wide continuous service temperature range and one of the lowest coefficients of friction of any solid. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). Exposure to service requiring elastic recovery or molten alkali metals will shorten service life.

Maintenance and OEM teams specify it across pharmaceutical and biotech, chemical processing, and food and beverage.

Reference part number TST439 when ordering; the item is sold individually. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.