This typewriter is also know as: Aztec, Optima, Zentronic, Bijou for UK exports, and PR'A'SIDNET.
Some interesting information: Seidel and Naumann (Dresden, East Germany) started their business around 1870. They had a machine shop and a great technical knowledge. Aiming to produce a profitable product they decided to manufacture typewriters. In 1872, they obtained a license to manufacture Singer sewing machines. This was mainly Naumann's idea, but apparently Seidel did not agree with him because he considered the risk too great, so he stepped away from the business.
In 1887, the firm began to diversify by starting manufacture of bicycles, and in 1892 they manufactured instruments to measure the speed of locomotives. The same year he began his studies for series production of typewriters. His first typewriter, Ideal appeared in 1900. It achieved a great success and sold extremely well around the globe. In 1913 a new Ideal typewriter was produced, but with World War 1 hostilities began, the firm soon began to make fuses for detonators, rifle barrels and other artifacts. After the war, S&N continued with its production of typewriters, sewing machines, and bicycles. They started with the first Erika, a three row portable, which was also sold in various countries. It is said that the typewriter got this name due to Naumann's daughter, Erika. The four row portable (of very high quality) was produced later.
When World War 2 started, the firm which had manufactured one million typewriters, had to use his factory almost exclusively to produce weapons of various types. Two large air attacks were made in the factory, the second occurred near the end of the war in April 1945, destroying about 75% of the area of production. The production of typewriters was resumed immediately after the war, concentrating its manufacturing in portables. Sadly production ended in August 1991.