This is another interesting chromatic with an original slide mechanism. F.A. Rauner must have produced this unusual slide chromatic after 1944. The DRWZ 261424 (“Deutsches-Reichs-Waren-Zeichen” -> basically the registration to offer a basic copyright protection for design or function ). The DRWZ initials were used in Germany after 1944. Before that, D.R.G.M. -> Deutsches Reichsgebrauchsmuster were the official initials for copy rights.