TST048 is an AS568-048 white PTFE (Teflon) 55 Shore D Back-Up Ring measuring an inside diameter of 4.739 in (120.37 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 4.879 in (123.93 mm). In service, this back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.
Expect good resistance to strong acids and bases, nearly all industrial chemicals, and oxidizing media. PTFE (Teflon) offers excellent dielectric properties 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).
Maintenance and OEM teams specify it across food and beverage, chemical processing, and aggressive-media pipelines.
Order part number TST048, sold individually. Check the compound against your process media, pressure and temperature before committing to a design. 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 2103-048 PTFE S/T BUP FDA
Actual Cross Section 0.07 inch (1.78 mm)
Actual Inside Diameter 4.739 inch (120.37 mm)
Actual Outside Diameter 4.879 inch (123.93 mm)
Measurement System Imperial
Product Category O-Rings - Backup Rings