425 PTFE SOLID BACKUP RING FDA

APG stocks the TST425SO, an AS568-425 white PTFE (Teflon) 55 Shore D Back-Up Ring built to an inside diameter of 4.475 in (113.67 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 5.025 in (127.64 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

It resists solvents, nearly all industrial chemicals, and strong acids and bases. That behavior comes from the compound itself: PTFE (Teflon) is valued for one of the lowest coefficients of friction of any solid and a very wide continuous service temperature range. Published continuous service range is -65°F (-53.9°C) to 500°F (260°C).

You will find this material specified across semiconductor fabrication, pharmaceutical and biotech, and laboratory equipment.

Reference part number TST425SO when ordering; the item is sold individually. Nominal inside diameter is listed as 4 1/2 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.