The Freezer Homebrewers CO2 Systems are built so you can convert a old or new freezer or small refrigerator (Low enough to use a tower on.) into a home draft dispenser for your homebrew. If you are using a freezer, you will want to have a temperature controlled thermostat to adjust the temperature to serving temperatures.
Freezers are a good choice because they are very efficient and have more floor space than small refrigerators. That means you can have a back up keg chilling while you drink the keg on tap... or have two on tap! Small refrigerators are good for small spaces but you have to be very careful about the inside dimensions. It would be a good idea to see this help page in either case. (If you have not already done so above.)