440 PTFE SOLID BACKUP RING FDA

Ordered as TST440SO, this is an AS568-440 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 6.725 in (170.82 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 7.275 in (184.79 mm). The back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

This material stands up to steam, oxidizing media, and solvents. PTFE (Teflon) is specified for excellent dielectric properties and near-universal chemical inertness. The material carries a published service range of -65°F (-53.9°C) to 500°F (260°C). Applications involving service requiring elastic recovery or molten alkali metals call for a different compound.

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

Stocked as TST440SO and sold individually. Application requirements vary, so validate compatibility with your process conditions prior to installation. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.