Magnetic small grid, dimensions: square, inner diameter 62.5 mm, outer diameter 76.6 mm, with eight circular magnets adhered—each 12 mm in diameter and 1.5 mm thick (though the actual delivered magnets are only 1.2 mm thick). When attaching the magnets, ensure that the magnetic poles of the two magnets on each face are opposite; this arrangement guarantees stability and ease of use when multiple boxes are magnetically joined. In addition, a pair of magnetic-attachment frames have been added to the edges for convenient vertical placement.