Reading the reviews of buyers on Amazon, I was very skeptical about the effectiveness of this anti-moles device. First discontent: the batteries not included batteries are not necessarily that one has in reserve at home ... of LR20! After resolving the problem battery, so I tried the unit. The next morning a superb taupiniète 1m anti moles !!! I decided to give a second chance to the machine and have the willingness to 50cm deeper digging into the ground. "And what do you think might happen?" ... No molehill next day or the day after, or on other days. My mole seems to have disappeared. Is it due to vibration ??? Anyway, I do not regret this purchase. Let's hope it continues ...