Hot and cold preservative M 220 heat stability +220 °C M 220 Silicone oil for heating baths. Brown. Vapour pressure at +20 °C: ~10-4 mbar at +150 °C: ~10-2 mbar Kinematic viscosity at +20 °C: 1000 mm2 s-1 (cSt) at +100 °C: 300 mm2 s-1 (cSt), Density 0.97