Brunsviga calculating machine circa 1900

Very nice calculating machine of the german brand brunsviga between 1900 and 1920, this machine was used in offices. This is the higher level of these machines because it has the ability to add, subtract and multiply. It works very well, a connoisseur has demonstrated it to me. There are tutorials on the net to learn how to use them. Black paint is worn by the fingers by the force of use.