I needed some M3 screws, but of course, what I wanted wasn't available in a single kit. I had to purchase a kit with many lengths, but it didn't have any nuts or washers (third picture, left box). Then, I had to purchase another kit just to get nuts and washers. That made it cumbersome because I would have to look in two boxes to get what I needed. So, the obvious solution was to create a custom box to hold all the screws, nuts and washers.