The Winter Fund, or Winterhilfswerk, was an annual charity drive organized by the Nazi party in Germany during the interwar and war years. German citizens were expected to give regular donations to the Winter Fund. These ‘donations’ were not necessarily voluntary. The newspapers printed a list of anyone who had not made a contribution. These people were often threatened and attacked until they donated to the fund.
The Nazi government did present donors with some gifts to acknowledge their contributions. These gifts often included small books or pamphlets about German history and folklore. For those donors who provided larger donations of money, food, or clothing, the Winterhilfswerk sent them a small pin, such as this hammer.
The pins changed on a regular basis. This meant that the Nazi Youth and other supporters could recognize if a person was up-to-date on their giving. The pins ranged from flowers, animals, regional occupations, and notable persons from German history (including Adolf Hitler, of course).
The hammer is a symbol of German Teutonic folklore. The Teutonic Order were a Germanic group formed to help Christian pilgrims on their journeys east. This gallant history is very much the way Nazis wanted their people to remember, and think of, Germany.