These boxes indeed are heavy duty. I previously purchased them for a client and, because I liked their sturdiness and ease of assembly, I purchased some for myself.

I use these boxes for many things. I pack things in them especially books, they are a great size for books, and heavy things. Storing things in them is great also.

These are very sturdy boxes and very simple to set up. Sometimes these kind of boxes are not so easy especially when it comes to the lid. Not so with these boxes. This is my second set.

These boxes are perfect for storage. They are very strong, easy to handle and are made from recycled material. I shopped around and these boxes were the best quality and the best price.

Good value and much better than the medium duty officedepotmaxstaples I had been using for file storage which cost more. Great for moving books (and look good for stacking).

I have purchased these boxes many a time. They are sturdy and allow for packing items to move or store that are actually manageable to lift after filling. Nothing has ever fallen through one, not even packed tightly with books. Love them.

The lid overlaps don't fold overlap very well to stay secured. The lid tabs cover the handholds and do not insert into the handholds when the box is full.

I've used these before for a move. As I use these for items (books, small appliances, etc.) which can get heavy after packing in one box; very handy for these items.

These boxes are very sturdy and did exactly what I needed. Currently I have them stacked and they are holding the weight beautifully. I recommend them!

I bought these boxes for moving my daughters apartment because they hold just enough to carry without getting too heavy. I packed them with dishes as well as books and they held up beautifully.