Nickelplated, hence the designation 'F'. It uses what you would call a stove tank, but it's a designated radiant heater, so it's not a conversion from a stove. But you could convert the radiator to a stove! That kit was called 701. Still, it's very close to a stove indeed, but I figured it must be along here any way in order to complete the 700-serie from Optimus.