The unit is solid and sturdy. The unit has 3 shelves. Two shelves on the larger side, and one shelf on the smaller side. The shelves require a total of 12 pins. There are four in the unit, holding up one shelf. I have 3 more pins as you can see in the last picture. You will need to get 1 or 5 more of these pins, depending on how many shelves you want to use. They are common and should be easy to find at a hardware or home improvement store.