A Gridfinity socket holder for 3/8in drive SAE/Imperial/American sized sockets. One model has “SAE” for the text, the other has a more whimsical 'MURICAN stamp, as seen in the cover photo.
Holds 7/16 thru 7/8 sized sockets in 3/8in drive. I used Husky brand sockets (Home Depot) for measurements, but allowed for some extra clearance so other brands may fit as well.
The author marked this model as their own original creation.