This is a dry erase marker and eraser holder. It was originally designed for use with a whiteboard wall. Since the whole wall is whiteboard, there is no tray to hold the markers and eraser, hence this creation. It holds 7 markers plus the eraser and can be attached to the wall with some double-sided foam tape or a Command strip.
This is just another reason to learn TinkerCAD. This item literally took under 30 minutes to design in TinkerCAD and solved a problem not only for me, but 5 other rooms in my office.