Heat transfer fluid is a much broader term than heat transfer oil.
When we talk about a heat transfer oil, its use is limited from about -115°C to +400°C.
For the use of heat transfer fluids at a higher temperature, we are actually talking about molten salts up to 540°C and liquid metals up to almost 1000°C.
Rodun International BV mainly operates within the range of +400°C and only owns thermal oil types.