This actually works! I have two cats, one very shy and one very bossy. I would say it helped to calm them both for there very different reasons.
My shy cat is now very friendly and fussy, much more confident.
My bossy highly strung cat is definatly calmer and kinder towards her sister.
There is a slight scent to the plug in but it’s a nice smell.
I wouldn’t say it’s a miracle worker but I’ve seen a difference and would buy again.