When my magnets arrived in torn & dirty cardboard boxes, my first reaction was that these were junk and that I would be returning them immediately. However, I went ahead and cleaned them up and tried them out - and was pleasantly surprised to find out that they really work. I’ve only used them on a chain hoist to position pieces on a couple of projects, they did the job with no problem. I don’t think that I would trust them to meet the outer limits of their holding capacity, they seem to be a good value for routine tasks.