The selectManyShuttle component provides a mechanism for selecting multiple values from a list of values by allowing the user to move items between two lists. The "value" attribute of the selectManyShuttle, like any other selectMany component, must be a List or array of values that correspond to a value of one of the contained SelectItems. If a value of one of the SelectItems is in the List or array, that item will appear in the trailing list. Looked at another way, you can change a selectManyListbox directly into a selectManyShuttle; instead of the "value" driving which items are selected in the listbox, it affects which items appear in the trailing list of the shuttle.