These magnets are wonderful. I had no idea what I was getting into by ordering these, but I am SO glad I did! I have cement blocks for walls and wanted to hang my collection of cheese knives/spreaders. I was very skeptical about these adhering and staying to the walls. I put one up and let it "cure" for 24 hours before attempting to stick anything to it. I fully expected it to fall during the overnight hours. It didn't! So I waited another 24 hours....still stuck. I hung 8 cheese knives/spreaders, of various weights, on the magnet, and they are all still hanging there! Not one has fallen, and the magnet is just as I originally placed it, no slipping/sliding. I wish I had thought this idea earlier...I have a lot of spreaders/knives to display. I am going back to order more! I highly recommend these to anyone wanting to display items.UPDATE:I ordered 5 more sets of these since they work so well. Only bad thing is: they did not hold to my cement wall. After 7-8 days, the magnet fell along with my cheese knives. So they are now on the side of my refrigerator, where they hold just fine since it's a perfect surface for this. I still recommend these even though they didn't stay on the cement.