Fits both TBS Glass ND Filters and Camera Butter Black Diamond Universal ND Filters (you slide them in from inside before installing the camera itself). Has holes on the back to quickly peek at settings/recording status without taking the camera out.
It has the biggest bumpers possible without being in frame in 4:3 ultra wide FOV. You can technically also use it to mount the camera vertically, but you'll have a part of bumpers in view then (example). I've been using this since April 2022 (as you can probably tell from how scuffed up it is) and have barely broken any ND filters and only a single Action 2 screen.
The author marked this model as their own original creation.