The Useful Temperature Range of PEEK related products for Chromatography is up to 100 °C (tubing); up to 125 °C (fittings).

PEEK is sometimes rated to 250°C but… It will not be as stable (lower burst pressure for tubing) as it is normally and some Solvents may interact Stronger than under RT with PEEK.

PEEK has to be used with caution with higher temperatures.