Ice Cream Makers come in three broad categories: Manual, Electric with a Frozen Container, and Electric with Refrigeration. All do the same thing, though.... Once you have made your base (sugar, milk, cream, and other flavorants), you will place them in the ice cream maker which provides a sub-freezing environment in which the ice cream will churn until it is frozen. The manual ones require you to add ice and salt and turn a crank (constantly), the containerized ones rotate the container for you which you have already frozen in your freezer, and the most expensive ones have their own built in freezing elements, saving you from keeping a container in the freezer.