In this post in the Van Life Q&A, a user asks:
Low-profile roof vent?
You can get a [manual opening version ](https://www.amazon.com/Maxxair-00-04000K-12V-Roof-Vent/dp/B0050EEO94?tag=beachfront08-20) that is much lower profile and let’s you control how open you want it to be.
But as mentioned in other comments the limitation is that you can’t use it in the rain and it’s pretty unstable on the lid if open while driving.
Personally I would go with the [white Maxxair fan](https://www.amazon.com/Maxxair-00-05100K-MaxxFan-Ventillation-Opening/dp/B002OWAIB8?tag=beachfront08-20) because I don’t think it is all that noticeable. Plenty of white work vans have stuff on the top. If you really want stealth, get a used ladder rack and stick a ladder on there to help hide the fan and disguise yourself 🙂