Property me worried for 2 Wühlmausfallen ca.400m2 lawn. The traps work. In the first week I have 3 voles and voles caught another 2 in the next week. Now is pretty calm. What is important when installing the traps which is placed the event in a transition. If one has put them there where a mound of earth is it does not work. Because here is usually only one gear that ends here and dig out the earth is used. So the case is always full dug with earth. I take a thin rod to the walkways of voles to find and then to place the case in a straight walkway. In any case, always wear gloves because the voles carry very sensitive odor are. The instructions on the package is also very helpful. Martin