2103-125 PTFE S/T BUP FDA

The TST125 is an AS568-125 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 1.299 in (32.99 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 1.505 in (38.23 mm). This back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

Expect good resistance to steam, solvents, and strong acids and bases. That behavior comes from the compound itself: PTFE (Teflon) is specified for a very wide continuous service temperature range and non-stick, non-contaminating surface characteristics. Service temperature is rated from -65°F (-53.9°C) through 500°F (260°C). It should not be specified for service in elemental fluorine at temperature or service requiring elastic recovery.

Maintenance and OEM teams specify it across aggressive-media pipelines, laboratory equipment, and chemical processing.

Reference part number TST125 when ordering; the item is sold individually. Nominal inside diameter is listed as 1 5/16 inch. Review your operating media and conditions against this specification before installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.