171 PTFE SOLID BACKUP RING FDA

APG stocks the TST171SO, an AS568-171 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 7.987 in (202.87 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 8.193 in (208.1 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

PTFE (Teflon) is known for near-universal chemical inertness and a very wide continuous service temperature range. The compound resists solvents, oxidizing media, and strong acids and bases. Continuous operating temperature is published at -65°F (-53.9°C) to 500°F (260°C). Exposure to molten alkali metals or elemental fluorine at temperature will shorten service life.

Maintenance and OEM teams specify it across chemical processing, food and beverage, and semiconductor fabrication.

Stocked as TST171SO and sold individually. Check the compound against your process media, pressure and temperature before committing to a design. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.