The Dahle Mega Magnet, measuring 45x45mm and sold in packs of 4, is a large, square magnet with a high holding force, used to attach posters, maps, and heavier documents to magnetic boards or metal surfaces where a conventional magnet would be insufficient. The 45mm square shape ensures a larger contact area and a more stable hold than smaller circular magnets. Sold in packs of 4, it's sufficient to hold a small poster in all four corners. It's a suitable accessory for meeting rooms, offices, and exhibition spaces that handle heavier materials.