It is a pouch for hex keys (also known as allen keys) from Prusa printer kits. Contains 6 holes of precise size for each key (2 x 1.5, 1 x 2, 2 x 2.5, 1 x 3). It is compact and protects the keys from damage allowing them to be stored anywhere (pocket, bag, etc.).
It is intended to be printed using TPU (or other flexible filament) since it relies on filament flexibility to hold the keys in place. Regular stiff filaments (PLA/PETG/ABS/etc.) simply won't work.
The author marked this model as their own original creation.