Heller

In German-speaking Europe, a unit of mass, a half Pfennig (the unit of mass, not the monetary Pfennig), = 1/512 mark. Taking the mark as the mark of Cologne in its oldest magnitude, 233.812 grams, makes the Heller about 456.66 milligrams.

The unit takes its name from the city of Schwäbisch Hall in Germany, which beginning around 1228 issued a pfennig coin that by 1430 had become so debased it was worth only half a pfennig.