Germany transferred its MP 18s to the German police forces after World War I. They also saw use in the hands of various paramilitary "Freikorps" during the aftermath of the German Revolution. In the 1920s a new, more reliable box magazine was developed for the MP 18 to replace the older snail-drum magazines. In 1928 a new version of the MP 18, the MP 28, saw the light of day, it featured the new box magazine as standard, a bayonet lug and a single shot mode. The MP 28 was manufactured in Belgium and Spain, and was widely exported from there, including to China and South America. Another variant based on the MP 18 was the MP 34 that was manufactured by the Germans through the Swiss front company Solothurn. The MP 34 was manufactured from the very best materials available and finished to the highest possible standard. Consequently, its production costs were extremely high. It was adopted by the Austrian police and army in the 1930s, and they were taken over by the Germans after German annexation of Austria in 1938. The MP35 was another interwar German submachine gun, designed by the Bergmann brothers. It was exported to Sweden and Ethopia and also saw extensive use in the Spanish Civil War. About 40,000 of the type were manufactured until 1944, with many going into the hands of the Waffen SS. The Erma EMP was yet another submachine gun from this period, based on a design by Heinrich Vollmer, about 10,000 were manufactured. It was exported to Spain, Mexico, China and Yugoslavia, but also used domestically by the SS, as well as being produced under license in Francoist Spain.