【Magic Ink】:The matching refill uses magic ink, it can automatically decoloration in 30 minutes after writing, so the copybook can be used repeatedly. 【Correct the Method of Holding Pen】:Each book has a detailed description of how to hold the pen, and a silicone handwriting aid is provided to facilitate children to master the method of holding pen. 【Easy to Practice】:The copybooks have three-dimensional grooves template design,which is convenient for kids to master writing. 【High Quality】:The paper is thick and not easy to smudges. Great for Kids Writing.