Freight elevator, or goods lift, is an elevator designed to carrygoods, rather than passengers. Freight elevators are generally required to display a written notice in the car that the use by passengers is prohibited (though not necessarily illegal), though certain freight elevators allow dual use through the use of an inconspicuous riser. Freight elevators are typically larger and capable of carrying heavier loads than a passenger elevator,generally from 2,300 to 4,500 kg. Freight elevators may have manually operated doors, and often have rugged interior finishesto prevent damage while loading and unloading. Although hydraulic freight elevators exist, electric elevators are more energy efficient for the work of freight lifting.