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A widget that provides an input listbox, accompanied with a listbox of selectable options. Order of selected options is saved. This component requires API version 41.0 and later.
A lightning:dualListbox component represents two side-by-side list boxes. Select one or more options in the list on the left. Move selected options to the list on the right. The order of the selected options is maintained and you can reorder options.
Lightning Components Developer Guide