I bought 6 pieces so my 92 year old mother could reach me anywhere in the house or yard. Everything worked fine at first, but after a week one of them was gone. I found him under her bed, he's dead and won't attack. She dropped the second one on the hard floor and it stopped working. I have emailed the seller via Revain but have not received a reply. Your records are so vague you can't find a contact number. I tried to find the number on the internet with no luck.