Items holds a TStrings object that lists the captions of the radio buttons in the group. (To add or remove radio buttons, edit the Items list from the Object Inspector. These captions become the "values" of the radio buttons, unless you override them in the Values property; when a button is selected, its value becomes the content of the linked field for the current record in the database. 

Items 

ItemIndex 

Values 

Restricting Field Values with Radio Controls