But when used with a M4 bolt

så den kan sættes på glas og andre glatte overflader

This means that the magnet does not break easily when you do experiments with attraction

To ensure optimal magnetic strength

Farvede power magneter 4x7 mm., 10-pak sort Auto-translated (NO) But when used with aBlack rod magnets, size 4x7 mm. These power magnets are coated with a black color. And you get them in a gift box with 10 pcs. From Trendform MAGNUM black. On these rod magnet, the magnetism sits on the ends. And the oblong format of rod magnets makes it easier to grap the magnets which is perfect as they are pretty strong (don't let the size fool you in relation to the strength of the magnets). Use the black power magnets to both steel boards,