These are DIY Furniture brackets for making your own shelves and such. No Supports required. To make a full box you need 4 Right Corner (Finright) brackets and 4 Left Corner (Finleft) brackets. The middle brackets are for adding shelves and you will need 4 at least (fin90). I used 4x1 in. Boards from home depot. The bookshelf you see required almost 2 spools (1 kilogram each) of PLA Filament and about 70 hours worth of printing. It is a big print, project ended up being more work than i had planned (especially when i found out that all lumber sold is undersized by about .250 in. and i had to redesign it all) but i'm very happy with the shelf. The shelf you see is about 5 ft. X 2.75 ft X 1 ft. and required a little over 100 screws.