The Soleus Oil Filled Radiator Heater (model NDY-15) is filled with an advanced conductible oil that never needs to be replenished. The oil filling this radiator heater is maintenance free - and it produces no fumes or flames. The Soleus radiator heater offers an adjustable thermostat with 3 different power settings (600 watt, 900 watt, and 1500 watt) that maintain a constant temperature with automatic on and off cycles. The heavy duty caster wheels and compact design allow this radiator heater