What is it?

Hint #1 - it produces HEAT!

Hint #2 - it connects to something

Hint #3 - Dad made it. :) 

Give up? Look below... it is the way our heater works now. The above picture is our new heater thermostat! Bet you never would have guessed that one! Plug it in and the furnace turns on, unplug it and the furnace stops. Pretty simple and we have HEAT! Dad ran a long, heavy duty extension cord from the furnace up the stairs to the ledge in the front hall. He then plugged in 1/2 of the brown extension cord to each end. On one end it connects into the furnace circuitry and the other end is above to complete the circuit. As soon as we can afford it, we will get a new programmable thermostat, but after no heat for hearly 10 days, we are happy campers.