This works for the Razer Kraken Tournament Edition, it's based (and requires the actual ears from) https://www.thingiverse.com/thing:2461166
I have the Kraken Tournament Edition that, as I have found out, have a different size from the ones in https://www.thingiverse.com/thing:2461166 (that btw this is a remix of but I can't select it? Makes sense...) so I made my own attachment! And with "made my own" I really mean mixing it together with https://www.thingiverse.com/thing:4818379 and doing it all with the correct proportions. You need to print the cat ears and the hook, then slide the hook in the ear, use an elastic band of some sort to wrap around the head band and you're done. Sort of, there's some play to make sure things would fit so the ears wobble a little and transfer a lot of noise to your ears, so glue them in place or anyway do something to stop them from wobbling. The result is nice.