The main part of the slow cooker is the base which contains the heating coils. These heater bands warm the bottom of the slow cooker. This heat rises up to the crock, heating both the bottom and sides to provide uniform cooking. How hot the slow cooker gets depends on the setting you chose. The temperature control, also found on the base, allow you to set the cooking temperature on high or low. The warm setting should only be used after food has been fully cooked.
The crock, normally made of glazed ceramic or heavy stoneware, holds the food you want to cook. The vessel is often heavy, but is made so that the heat is constant and evenly distributed. Although some vessels are built in, most are removable for easy preparation and cleaning.
The final and perhaps most important component of a slow cooker is the lid. The lid keeps heat and steam inside. Without it, the cooker could not reach the appropriate cooking temperature. The lid also works as a baster, continually creating a moist environment for the food.