The K&F Concept extension adapter is a sophisticated and robust addition for anyone who wants to get more out of their DJI Osmo Pocket 3. The accessories transform the small camera into a more versatile setup, whether for vlogging, interviews or creative perspectives with additional accessories. The workmanship is high-quality:
The aluminum cage feels sturdy, is precisely manufactured and ensures a safe feeling when handling. The numerous mounting options are particularly positive: 
1/4 inch thread, 
Cold Shoe Mount, 
Arca mount 
and action cam interface leave nothing to be desired! 
Thanks to the magnetic closure, switching quickly between different shooting situations is also pleasantly quick. Particularly practical in everyday life:
The TF card slot remains accessible despite the adapter being mounted, so that the memory card can be quickly changed without removing the frame, a well-thought-out detail. A small downside is the handling when inserting and removing the camera. That works, but not quite as smoothly as you would like; a more intuitive mechanism would be desirable here. The additional weight is also quite noticeable during longer handheld sessions. My conclusion:
If you work regularly with the Osmo Pocket 3 and want to use accessories flexibly, this extension adapter is a solid, functional upgrade!