DeLonghi Dragon 4 Oil Filled RadiatorsChimney effectThe Dragon 4 Technology is designed to be both aesthetically pleasing and functional. In a pure, brilliant-white colour, its stylish uncluttered design makes it ideal for any home: providing a touch of refined, essential and harmonious style. Chimney Effect - The De'Longhi TRD4 0820T Dragon 4 Oil Filled Radiator convects air through its "chimney" and cold air is channelled through the hottest part of the radiator, accelerating hot air through vents for effective heating and providing a fast flow of hot air that quickly warms the whole room. More Radiant Surface - With an enlarged fin shape, it delivers an increased chimney (convective) effect for faster hot air flow . Its new enlarged battery design means it provides 25% larger radiant surface than the previous Dragon 3 model and ensures faster air flow emission and increased chimney effect for better comfort. DELONGHI 'Dragon 4' TRD40820T Oil Filled Radiator in White