Solar fluids transfer heat from solar energy into a solar consumer. SOLARTEN anti-corrosion ecological heat-transfer fluids have a low freezing point, while containing non toxic corrosion inhibitors and stabilizers helping to reach better thermal stability and extended lifetime. SOLARTEN SUPER is a fluid based on mono propylene glycol, and an extended warranty for Regulus flat plate collectors is valid only when this fluid is used. SOLARTEN HT is a fluid based on heavy glycols for thermally highly stressed solar thermal systems. It must not be mixed with Solarten Super fluid, and an extended warranty for Regulus evacuated-tube collectors is valid only when this fluid is used.