Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Doesn't Work on Kitty Monsters

I can see how this product might work for some cats, but it didn't even phase ours. Just when we think we've hit on something that might be effective for our 3 1/2 year old Maine Coon, she proves us wrong! The only beings in the house annoyed by the sonic blast were the humans - had to send it back.