Updates over on Printables: https://www.printables.com/model/1507214-dji-o4-air-unit-speedybee-bee25-vtx-mounting-parts

By default the Bee25 does not have a way to mount the o4 air unit which is why I made these case and camera adapter pieces for.
The camera adapters utilize the default DJI provided camera cover + screws. Additionally the adapter provides tilting of the camera.

The VTX case encases the whole board providing additional protection for surface mounted components. No screws needed as the case braces to the chassis. Unfortunately you have to detach the camera canopy from the drone body the get access to the USB port but consequently it is protected from debris as the ports face the body not ground.

All Up Weight with 4s 850MAh battery is 247g without an receiver (using DJI SBUS with DJI FPV Remote Controller 2). 
Weight without battery and receiver is 150g. 
Measurements are without the second antenna piece as o4 air only uses one antenna.

Print in TPU. Detailed print settings are in the .3mf-file.

Flight tested, no issues so far. 

Plans (2026 summer):
- Add antenna mount to top so the mounting is a lot faster.
- Tighten the bottom gap, so no dirt can access the case from bottom of the case.

Images show how to wire and orient the VTX. I am using the stock length cable here. I have also extended the coaxial cable cover part that is seen in the images.

Just an FYI: 
The DJI o4 Air unit uses 1-3S Voltage and the 3in1 cable from the drone is wired to VBAT. 
The Bee25 is a 4S drone resulting in over voltage. 
You need to unpin the VBAT wire and replace it with onboard VTX 5V pad to the cable.