History of the German Fuze
The German ECR (Electrical, Condenser , Resistance) fuze was first manufactured by Rheinmetall in the 1930's, and was designed by Hubert Rhuleman
The normal type of bomb fuze is 110 mm long by 50 mm wide (measured from the head to the base) the fuze consists of usually 2 charging pins, although if the fuze has only one circuit, the (17) for example then only one is present, the other is a dummy.
Below this is the shoulder, this may contain 3 fixing screws, its this location that the various markings are found,consisting of type of fuze ie EIAZ is an electrical impact type. Next is a ringed number NB this is very important for example a ringed (17) is a long delay clockwork fuze, it's this type of fuze that is longer in length, the clockwork portion screws into the base and is 142 mm long. then there is the Triagramme or manufacturers mark which can be 2 or 3 letters ie RhS is Rheinmetall (Sommerda ) Plant.
On early fuzes the Germans marked which bomb the fuze was to be used for, marked C50 this was the 50kg the standard bomb used at the beginning of the war.
Then the batch code ie 2a is batch 2 sub batch a, this allowed any faulty batches to be easily found, finally there is the inspectors stamp (waffenampt ) Rheinmetalls inspector was number 56.