Convert from as, ass [Northern Europe] to zentner [Germany]

Unit Definition (as, ass [Northern Europe])
The as, ass [Northern Europe] is a traditional unit of mass for gold and silver, used in most of northern Europe but not in England. The unit varied in size from about 48 to 58 milligrams (0.75 to 0.90 English grain).

Unit Definition (zentner [Germany])
The zentner is a traditional German unit of weight or mass, comparable to the traditional quintal and to the English hundredweight. Similar units were used in Scandinavia. Originally the zentner was equal to 100 pfund, or German pounds. 100 pfund varied from 110 to as much as 120 pounds avoirdupois (49.9-54.4 kilograms), depending on the market. After the introduction of the metric system in Germany, the zentner was redefined to equal to exactly 50 kilograms, which is about 110.231 pounds. In English, the zentner is commonly spelled centner.