2103-389 PTFE S/T BUP FDA

Part number TST389 is an AS568-389 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 19.953 in (506.81 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 20.373 in (517.47 mm). A back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

The compound resists nearly all industrial chemicals, strong acids and bases, and steam. PTFE (Teflon) delivers excellent dielectric properties and one of the lowest coefficients of friction of any solid. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service.

Typical settings include food and beverage, aggressive-media pipelines, and laboratory equipment.

Reference part number TST389 when ordering; the item is sold individually. Nominal inside diameter is listed as 20 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.