For anyone interested in a coolerbator, this is the thermostat I use.
http://m.homedepot.com/p/Camco-Metal-and-Plastic-Lower-Water-Heater-Thermostat-15417/100116468/
http://m.homedepot.com/p/Camco-Metal-and-Plastic-Lower-Water-Heater-Thermostat-15417/100116468/