You can use any cooler! All you need is:
cooler
Flexwatt
connectors & wire (for the Flexwatt)
aluminum tape(to tape the Flexwatt down)
egg-crate
water bottles
thermostat
thermometer with a prob
In a nut shell, get the cooler and drill a small hole in the side for the Flexwatt wire and prob. Run the power cord into the cooler through the hole and connect the power cord the the Flexwatt using the connectors and insulators and tape the Flexwatt to the bottom of the cooler(plug in for a couple of seconds and make sure it heats up). Place some water bottles on the bottom. Then place a piece(cut to fit) of egg-crate on top of the bottles. Put your tub (filled with what ever you are using) on top of the egg-crate. Plug your Flexwatt into the thermostat and set it to the desired temp, and run the thermometer prob through the hole into the cooler. Fill or cover the hole to stop any heat loss.
And that is pretty much it, unless you want to install a small computer fan.
Hope this helps, any questions just ask!