Starting from any point in the Converter screen, you may touch the [Search] button to bring up the Search display:
In the above example, "mp" was typed into the 'Search for' box, and the units or categories that contained "mp" were automatically listed. When you see the listed unit you are searching for, touch that unit to automatically display it in the Converter:
In the above example, the search item "mile per hour" was selected, and the Converter automatically displayed the "Speed" category and the "Mile per hour" unit.
You may also use the Search function to select a unit category. For example, touch the [Search] button and scroll to the category you want:
If you want to see Mass units in the Converter, touch the "Mass" item in the search list, and the Converter will display that category with the previously-selected units: