Yes they are heavy duty ... BUT!!!.. I wish they made 'bigger binders' that did NOT have 'D' rings which are only round on one side .. the 'Left' side. When I try to turn the pages they always get stuck at the top where the 2 sides of the rings meet.. because both sides point downward where they meet ... and the pages get stuck!!! Older binders used to have 'round rings on both sides!!
This binder was not at all what I wanted when I ordered it online. I don't like the "view" binders & thought I was buying a non-view. Found out from my store the 3" green non-view are no longer carried...why?? Also this binder didn't close correctly so I wouldn't have kept it anyway.
Overall this is a good product and will stand up to lighter use. Several years ago Staples offered a "heavy duty" binder with thicker top & bottom cover and they seemed more sturdy. I hope the cover bindings will stand up to many cover opening & closings. We'll see.