**2107-352 PTFE SPIRAL B/U FDA

Ordered as TSP352, this is an AS568-352 white PTFE (Teflon) 55 Shore D Back-Up Ring with an inside diameter of 4.85 in (123.19 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.27 in (133.86 mm). The back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

PTFE (Teflon) is specified here for one of the lowest coefficients of friction of any solid and very wide continuous service temperature range. This material stands up to oxidizing media, steam, and solvents. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). It is not the right choice where molten alkali metals or service requiring elastic recovery are present.

Maintenance and OEM teams specify it across pharmaceutical and biotech, semiconductor fabrication, and chemical processing.

This item is sold individually under part number TSP352. Nominal inside diameter is listed as 4 7/8 inch. Review your operating media and conditions against this specification before 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.