Convert from firkin [butter, soap] to catty [China]

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).

Unit Definition (catty [China])
The catty [China] is a weight unit of the colonial period in East and Southeast Asia, originating as the kati in Malaya. The catty varied a little from market to market. Typically it was equal to about 4/3 pound avoirdupois (604.79 grams), and it is still equal to that weight in Malaysia. In China, the catty was identified with the jin, a traditional Chinese unit.