Buttons maintains a list of TToolButton instances. All tool buttons that share a TToolBar parent have the same height and (except for separators and dividers) the same width. Other controls on a toolbar are held in place by invisible separators, which are automatically created and destroyed. 

To add tool buttons to the toolbar at design time, select the toolbar, right-click, and choose New Button. To create a space (separator) between one button and the next, select New Separator. To create a divider between buttons, add a button and set its Style property to tbsDivider. Other controls may be added to the toolbar directly from the Component palette. 

TToolBar.Buttons Property