*2107-343 PTFE SPIRAL B/U FDA

APG stocks the TSP343, an AS568-343 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 3.725 in (94.62 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 4.145 in (105.28 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

This material stands up to solvents, steam, and nearly all industrial chemicals. That behavior comes from the compound itself: PTFE (Teflon) is specified for one of the lowest coefficients of friction of any solid and near-universal chemical inertness. Published continuous service range is -65°F (-53.9°C) to 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 chemical processing, pharmaceutical and biotech, and laboratory equipment.

Stocked as TSP343 and sold individually. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.