Extreme heat and cold pose no problem for these resilient sealing washers. They won't deform or lose strength at temperatures as low as -400° F and as high as 525° F to handle everything from liquid nitrogen to heating elements. They are also the most chemical-resistant plastic washers we offer to withstand a wide range of acids, bases, solvents, and corrosive cleaners. ePTFE is more flexible than standard PTFE, so these washers compress easily to hold a strong seal. Reuse them a handful of times, as long as the material isn't damaged.