From what i can tell it depends on what country your in. I found them on both Amazon US (where I'm assuming you are) and Amazon UK (where i am)

US link https://www.amazon.com/Brookstone-Wireless-Headphones-Bluetooth-Changing/dp/B01N06LH7I/ref=sr_1_4?s=books&ie=UTF8&qid=1545679755&sr=8-4&keywords=Cat+ears+headphones

UK link https://www.amazon.co.uk/dp/B073Q58V66/ref=asc_df_B073Q58V6657656088/?tag=googshopuk-21&creative=22122&creativeASIN=B073Q58V66&linkCode=df0&hvadid=309785494452&hvpos=1o1&hvnetw=g&hvrand=3537484189992817801&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9045999&hvtargid=aud-545868369748:pla-349264315408

They say they're from different companies but from what i can tell they're the same headphones, just sold by a different name in different territories. If the UK ones can do international shipping id suggest going for those ones instead because the US ones are astronomically more expensive (although even the uk one is still very expensive). I was lucky enough to find mine sold as a broken pair in a pawn shop for cheap which i bought and then fixed.

You might also have some luck if you look on ebay and the likes if you want to maybe find them cheaper for second hand. Just look for "brookstone/axent wireless cat ears headphones"

Hope i could be of help!