Environmental protection material: Magnet stickers are made of hard cardboard and strongly magnetic materials. The hard cardboard is odorless and non-toxic, and the magnet is strongly attached to the cardboard and will not fall off easily. The edges of magnet stickers are rounded and polished so that they will not hurt your child’s hands without cutting your hands. At the same time, the surface of the magnetic sheet is covered with a glossy waterproof film, which is more durable.