Hard to believe, but it worked immediately. Had to about 400 m² lawn 30 molehill and several Wühlmausspuren. Have beginning March 2 mole EX Solar (ca 30 m distance) simply plugged in 2 molehill and neither new nor new hill Wühlmausspuren incurred. Despite freezing rain and they work perfectly so far. Inexpensive, monitiert fast, stable quality, easy to use, and we are thrilled at the beep you get used to very quickly.