The author remixed this model.
Remix of the original screw on bracket to slide into the corner brackets on my Costco shelves in my garage. These are great for hanging up lighter weight objects like hoses, extension cords, or my jacket when I'm out in the garage. They slide into the brackets/supports of the shelves. These were from Costco, but I've seen many similarly patterned shelves at the various box stores.
Ensure you setup the print so the pins are solid. They aren't super strong just due to the limits of the material, but you don't really want to be hanging anything heavy on them when they are clipped to the shelving unit, lest it tip over.