Vocabulary:

The acronym D.R.W.Z. with or without punctuation stands for Deutsches Reichswarenzeichen, meaning that an item marked as such was officially registered under trademark laws inside all of the Germany states and not only locally registered as it was the case before the introduction of centralized registration. Note that many people quote this acronym as standing for Deutsches Reich Warenzeichen, which is grammatically wrong and also ommits the letter 's' after Reich. This results in shifting the weight of pronounciation on 'Deutsches Reich' alone, but this acronym has nothing to do with the Third Reich as many sellers want to imply so to catch the attention of certain 'collectors'.

D.R.W.Z. registrations were introduced 1891 and if you are dating items you should hold in mind that even during Allied occupation up until 1949, registration procedures remained untouched and still used the D.R.W.Z. registration documents, which of course explains why such marks can be found on products actually manufactured up until 1952 as the registration itself was valid for three years. As from the end of October 1952, all registrations were definately marked as 'Deutsches Bundeswarenzeichen' (D.B.W.Z.) or simply 'Eingetragenes Warenzeichen'.