568-438 PTFE ORINGS FDA

The TFE438 is an AS568-438 white PTFE (Teflon) 55 Shore D O-Ring with an inside diameter of 6.225 in (158.12 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 6.775 in (172.09 mm). This o-ring creates a positive seal at flange, piston and rod interfaces without added hardware.

It resists steam, solvents, and strong acids and bases. That behavior comes from the compound itself: PTFE (Teflon) is specified for near-universal chemical inertness and non-stick, non-contaminating surface characteristics. Rated temperature range runs from -65°F (-53.9°C) to 500°F (260°C) in continuous service. It is not the right choice where molten alkali metals or service requiring elastic recovery are present.

You will find this material specified across laboratory equipment, food and beverage, and semiconductor fabrication.

TFE438 ships individually. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.