I've just bought two first fight against regular visits boars in my garden and saw that they have deserted parts of the garden where I had placed the two terminals, I deduced that it was effective and bought two autres.Avant even receiving my order, they returned at night and dug a rut before one of the two terminals and had covered with earth ..... As for the second, I noticed that she did not emit more ultrasounds, batteries with rusty inside - after just 6 months of use -.....