2103-205 PTFE S/T BUP FDA

This back-up ring is supplied in AS568-205 white PTFE (Teflon) 55 Shore D supplied with an inside diameter of 0.421 in (10.69 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 0.699 in (17.75 mm), catalogued under part number TST205. It extends o-ring service life by supporting the seal against extrusion under high pressure.

Expect good resistance to strong acids and bases, oxidizing media, and steam. That behavior comes from the compound itself: PTFE (Teflon) offers a very wide continuous service temperature range and excellent dielectric properties. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. It is not the right choice where service requiring elastic recovery or molten alkali metals are present.

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

TST205 ships individually. Nominal inside diameter is listed as 7/16 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.