Convert from libra [Italy] to arroba [Spain]

Unit Definition (libra [Italy])
The libra [Italy] is a traditional unit of weight. The libra was the Roman unit from which the English pound is descended; the symbol "lb" for the pound comes from this unit. The traditional Italian libbra was often of similar size, but a wide variety of libbras were used in Italian markets over the centuries. The word "libra" is sometimes used now for the kilogram, a much larger unit.

Unit Definition (arroba [Spain])
The arroba [Spain] is a traditional unit of weight in Spain and Portugal, equal to 1/4 quintal. However, the Spanish and Portuguese quintals are of different sizes. In Spain, the arroba equals 25.36 pounds (11.50 kilograms); arrobas of very similar sizes were established in the Spanish speaking countries of Latin America. The arroba has also been used as a metric unit equal to exactly 15 kilograms. The name of the unit comes from ar rub', Arabic for "the quarter."