If you're using two different pieces of flexwatt for the double enclosure and they both need to be the same temp then you can just plug them into a multi-plug or a surge protector (or have them parallel wired) and then into the thermostat. But if both sides need to be different temps then you'll need two thermostats. Kaorte found a good inexpensive digital thermostat if you're not looking to spend $100 on one. here