I remixed this from this thing https://www.thingiverse.com/thing:5179135. I made it smaller, made the distance between support areas bigger for phones with cases and added a ring to the back for a keychain or a carabiner. Only really need supports on Part B. Assembly is required when done. Print and enjoy.

Prusa

I3 MK3S

Doesn't Matter

Yes

.3 mm

15%