You can find pictures of the various adapters here: www.nuki.io/adapter - though I have to say, your cylinder doesn’t look right for any of them as the shank appears to be offset. Possibly the green one? My experience has been that the adapters (which are made of plastic) are not that durable if they don’t fit exactly.
Me too! On my first attempt the adapter was a little loose on the shank of the lock and the hole developed a crack. I’ve now added a slip of cardboard so that it fits snugly, and that’s working well.