The design with the knotwork was inspired by original Nordic and Viking styles. Makes a great Scandinavian, Nordic or Viking gift.
Thor is the Norse god of thunder and the defender of Asgard. The original Mjölnir or Mjollnir (Thor's hammer) was made by the dwarfs brothers Sindri and Brokk. It had special powers and is a symbol of Thor's strength. Thor's Hammer is not only the most powerful Norse weapon but is also a symbol of fertility. This is my own design but it was inspired by styles of known original Mjölnirs and other Viking art.