Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Worthless

I bought this product thinking this would be a great way to deal with my small dogs barking. However, turns out it was a big waste of money. I can't even get it to stay on my dog without flipping over on my dog's neck! I have tried tightening it, readjusting the collar, etc. and the stupid thing doesn't stay like the directions say to place it. Useless product! Need to strategy...