Convert from centner [Germany] to firkin [butter, soap]

Unit Definition (centner [Germany])
The centner [Germany] is the English name for a German weight or mass unit, the zentner, equal to 50 kilograms or about 110.231 pounds. The name centner should not be used for the cental.

Unit Definition (firkin [butter, soap])
The firkin [butter, soap] is a traditional unit of weight for butter and soap, equal to 4 stone or 56 pounds (about 25.40 kilograms).