Part number TST149SO is an AS568-149 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 2.8 in (71.12 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 3.006 in (76.35 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.
It resists steam, strong acids and bases, and solvents. That behavior comes from the compound itself: PTFE (Teflon) is specified for near-universal chemical inertness and one of the lowest coefficients of friction of any solid. The material carries a published service range of -65°F (-53.9°C) to 500°F (260°C). Verify compatibility before use with elemental fluorine at temperature or service requiring elastic recovery.
You will find this material specified across chemical processing, laboratory equipment, and aggressive-media pipelines.
Order part number TST149SO, sold individually. Nominal inside diameter is listed as 2 13/16 inch. 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.
Description 149 PTFE SOLID BACKUP RING FDA
Actual Cross Section 0.103 inch (2.62 mm)
Actual Inside Diameter 2.8 inch (71.12 mm)
Actual Outside Diameter 3.006 inch (76.35 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings