Rune Binder and myself appear to share an interest in this particular hammer. Like Rune Binder I feel that this form of the Hammer has a special and sacral quality because not only is it an historical rather than a contemporary version but it connects us also to the great Runic and folkish revival of 1930s Germany. This was one of the versions produced by that great German silversmith Otto Gahr.
Those who felt a particular affinity with the Gods of their ancient Germanic ancestors would choose to wear the Hammer rather than the xtian cross, although the cross itself was not originally a xtian symbol but an ancient Aryan and Germanic solar symbol which we revere today as Woden's Eye.
SS and Wehrmacht soldiers no doubt felt a source of comfort, protection and vitalising energy by wearing the Hammer amulet into battle, tucked beneath their tunics of course. The fact that Otto Gahr produced a number of different styles of Hammer is an indication to me that there was a demand for this product. This is further evidence for the revival of Germanic religion in the Third Reich under the protective hand of Heinrich Himmler who himself wore a Hammer amulet under his clothing, although there is some dispute as to which version of the Hammer he wore. From time to time I have seen some copies of Gahr Hammers for sale on the Internet but they tend to sell very quickly.
Rune Binder makes the very valid point that we should try and avoid imported Hammers from Asia. I agree with him. However it is not always possible to ascertain where and by whom a Hammer has been made. The only sure way to know that a Hammer has been made in Europe or by European craftsmen or manufacturers is to visit the websites of sellers who clearly manufacture their own. However in these days of international trade even though I always use English, German, European and American traders we cannot know for sure. I have a large collection of Hammers of all styles, sizes and material. They are a mix of traditional and contemporary or modern styles using traditional motifs.
If you are unsure of the origins of your Hammer rather than cast it away I suggest that you perform a rite of sanctification using a sprinkling of salt and running water with a suitable invocation to Thunor to bless it and make it His own. Even better if you can expose the amulet to rain water that has been blessed by thunder.