So as many other I saw jb video ( https://youtu.be/Z8ztDFvQt88 ) about keeping the vtx and specially the DJI O3 unit cool when working on the banch or while waiting with battery in field (those GPS down time are tough).
So i give it a try and came back with cool design using 5015 fan that concentrate the airflow to the vtx, and with shield on the inlet so nothing could suck in and demage the vtx itself.
It as good connection on the outer nozzle of the fan but also have holes to be hard mount.
attach the two parts with m4 screw at list 10 mm depth.