This mount is designed to hold a dry box on the Flsun Q5.
It is screwed to the places where the normal coil holder is attached.

I use the following boxes:

https://www.amazon.de/gp/product/B07Z69Z5FG/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&th=1

Printing Notes:

Resolution: 0.2
Filling: 30
Walls: 3
Material: PLA
Supports: -
 

Looks small at first glance, but has been holding boxes securely in place for over a year.