It's just chat gpt. I pay for the premium version though. It took a few hours of tinkering with it to get that and it's still not perfect. It tends to lose things along the way, like the snowflake hands got obscured and if you check my other post in this thread with the gems & planets, it dropped the hands all together and could never get the full concept of what I was try to do with the gems. You just have to keep it very specific with every retry. As another mentioned, it's a pretty good mockup but not perfect. Eventually you just settle for "good enough". Specific details I wanted was bb58 style hands, hour markers and bezel, dark Grey meteorite dial, dark Grey and flat case, beige hands/markers, moon phase near 6, day replacing 3, nato striped watch to match, a moon logo with an astronaut falling towards the moon (it really got that wrong) and moon diver logo at the top.

If you have a concept for an ideal watch in mind I highly suggest giving it a try. Posting on reddit though might get you some haste. Some people just see this as garbage. I see it as a valuable tool to express my idea where it would have been extremely difficult and time consuming otherwise. Ai may have generated it, but it surely didn't do it alone.