Wow! Thanks everyone for all the suggestions - there's a lot of products to look at researching here.
They're due for the annual check up in a couple of weeks, so I'm going to discuss these options with our Veterinarian and try to figure out what would work best!
I looked around at alternatives on Amazon and not a one has more than a 3 Stars on reviews.
:-/ I'm open to alternatives - I just am not sure that there are any that are better.
Oh, I didn't mean using essential oils. I meant opening up the feliway refill and putting it inside a (clean, unused, new) essential oil diffuser.
Sorry if that wasn't clear.
The reason I was hoping to find a diffuser alternative rather than using the alternative products (such as the spray)...
I was considering trying Feliway again to help keep my cats calm and happy during an upcoming extended trip where they will be left at home with a pet sitter, but the last time I used one of the diffusers it leaked all over the place and made a really big mess. Reviews on the feliway diffusers...