This is referring to the environmental conditions of the whole Findenser unit, considering what the internal parts can withstand (so is not referring to chemistry applications / solvent boiling points etc.).
You should not exceed 60°C when oven drying (or 50°C if cleaning in a dishwasher). This is because high temperatures can weaken the seals etc., and lead to product damage/failure.
The minimum of 0°C is because the Findenser contains water (as heat transfer fluid) sealed in between the glass body and finned aluminium jacket. If the Findenser gets cold enough, the water inside Findenser could freeze and expand. To prevent any risk of internal damage, Findenser should not be exposed to freezing temperatures (e.g. left outside in a vehicle on a cold night).
For more information, please refer to the Findenser instructions and website FAQs.