Attached are some pictures of 4 variations of the lafette wrench, and what the wrench is used for on the lafette. Since the lower part of the MG34 lafette is the same as the MG42 lafette, the wrench works the same for both.
The Norwegian wrenches are easier to find, and not as collectable as the German wrenches, so they aren't nearly as expensive. The German wrench often sells for $200 - $250, depending on condition.