Nelson Gulf Stream Bird Bath Heater Model 6200 Keeps Water From Freezing In Your Bird Bath All Winter Long. Water is vital for bird's survival in winter. Gulfstream bird bath heater keeps water at 40 to 50 degrees even in sub zero temps. Cost just pennies a day to run. Use this immersion type electric 200 watt, 120 volts heater in plastic, concrete or pottery bird baths. Heavy duty, grounded electrical cord. About 7.25" x 2.75" x 1" plus cord. UL listed outdoor extension cord and GFCI outlet not included.