A toolbar contains a set of actions for managing or manipulating the content of the current view. On the iPhone, it will always appear aligned at the bottom edge of the screen, while on the iPad, it can also be displayed aligned at the top of the screen.
Similarly to the navigation bar, the background fill of toolbars can be modified, is translucent and blurs the underlaying content by default.
Toolbars should be used when a specific view requires more than three primary actions that would hardly fit or would look messy in the navigation bar.