Originally Posted by Camilo

I will bet (fake) money that you're wrong about the ZTTO cassette. If it fits on the free hub.

If your hub has a wider groove, it is adjacent to a narrower spline on the hub.

The cassette must have a corresponding wider spline adjacent to a narrower groove. This is how loose cassette sprockets are oriented properly.

I happen to have a ZTTO cassette that is fully compatible with a Shimano-standard hub as I describe above

Post a good detailed picture of each and prove me wrong! Here's one I pulled from the web.