I use these in my craft room to hold up cutting mats and they hold with ease. I have a few left and will eventually use them in my workshop, as they are truly multipurpose. They are small and don't take up a lot of space. If you are looking for magnets to hold anything up, these little guys do a great job! I did not test the 12lb limit, but tested on something 6-7lbs and it held with no trouble.