The neodym-magnets used by us are a multiple stronger than the traditional ferrit-magnets at the same size. We use only neodym-magnets with enough strong magnetizations (N48 - N52). A good and durable galvanization for meodym-magnets is Ni-Cu-Ni. So they are coated with nickel therefore silver-colored.
The size of the magnets is optimized for the particular article-size dependent from the aspired magnetic strength without getting too heavy with them. Our products are complete only about 4g to 30g heavy!
Our small magnets kann lift steel weights weighing several kilograms. The manufacturer informations are diverging in this measured variable a little bit.
We have made the following test by ourselves. We have counted the number of DIN A4-pages (80g paper) a single magnet can hold on a clean lacquered sheet metal surface without getting into sliding.
For our smallest magnets we counted 10 pages, for our biggest even 25 pages. Cheap ferrit-magnets for pinboards from a normal hardware store allow only 3 pages! And please consider that in our case this magnetic strength is almost duplicated because two magnets gravitate towards one another.
I think, we have described the strength of our magnets enough with that.