"Bought the item a week ago and haven't had any complaints.
When I researched the item I noted that the reviews were either very high or low with "I'm returning it." This, and my experience, suggests the effectiveness depends on the dog.
After installing the battery I pressed the manual button. One dog jumped and went up the stairs and the other headed for another room. I set it by the front door with a clear shot down the tiled hallway. Almost at once the barking noticeably decreased. I’d hear a bark or two and then nothing. I noted they started staying at the corner of the hallway and stopped charging to the front door.
My daughter came with her two and I saw the item isn’t all things to all dogs. One of hers simply didn’t notice it.
I pull the battery at night so if there are prowlers my doggie alarm will go off. I’d change the design to have an on/off switch but other them that, noting.
My advice is to plan to return the item (save the box and slip) and try it. Location seems important as my hallway has lots of hard surfaces to bounce sound. Tonight I picked up the unit and watched one of my dogs scoot. No doubt she know what it is."