This is a hex shaped base for holding metric Bondhus Allen Keys. The side that holds the square end keys has a square edge, and then side that holds the ball end keys has a large fillet, so it's easy to know which is witch. Sadly the SAE key sets (yellow) are a different shape than these metric ones.
I just printed this in black PLA+ using a brim. Nothing fancy.
The author marked this model as their own original creation.