Air carriers are what people usually think of when they hear the word "carrier." One of the most common types of conveyor, an overhead conveyor is usually used in a production facility to move parts from one location to another. They take advantage of the generally unused vertical space above the work area. Using curved sections or even with lifts, they lower parts to the operators' level and raise them to higher elevations. Overhead conveyors can pass through production areas that humans can't appreciate through furnaces and robot work cells