These containers are incredibly well built. They are thick, but designed in a way that makes them stronger than they are thick... or perhaps stronger than their thickness alone could provide. I was totally amazed at how good these things are.These containers also stack well. Other containers really bind up when stacked, but these come apart quite easily. Interestingly, they can also be turned to stack on top rather than inside each other.The only bummer for me was that there were no lids. I get it. The purposes these serve means that some may not need tops. For me, they do. I bought the tops separately since I did need them. They also fit great and stay securely attached.I am really happy with these containers. Lids or not, they are high quality!!!