content: The knife on the can opener will not penetrate some cans, therefore it will not open them. Some can edges appear to be different heights which probably contributes to the problem. It never occurred to me that it would be unsatisfactory so when I unpacked it, I discarded the box and packing, otherwise I would have returned it. I am very unhappy with this cutter, especially as much as it cost and will shop around for another kind. Would not recommend.