When a customer needs their custom cable to perform in truly extreme conditions, we recommend Teflon-insulated wire. Teflon offers outstanding resistance to any type of disturbance or wear you could think of — other than, like, nuclear radiation. M16878/4 wire is a well-known military-specification wire rated for 200°C (and -70°C), but it is the most expensive wire type that is readily available on the market.