This is a 6 inch Cookie tin with a bulb and thermostat. Total cost $5.00 small heat lamp from Walmart, cooking $2.00, Electric Thermostat (lower) Lowes $8.00. Total cost $15 bucks beats the $40.00 heated waterer. Thermostat turns on light. If it gets too hot it will shut off as a fire prevention. As it cools down, It will turn back on.