Hey there, if you're tired of messy shelves and disorganized books, these PVC shelf dividers are exactly what you need! You get 20 pieces that measure 20cm long by 12cm high with a 1mm thickness - perfect for standard library shelves, classroom bookcases, or even closet organization. The transparent PVC material is 98% crystal clear, so you can easily see your books or products while keeping everything neatly separated. Each divider has a 3cm label area where you can write with marker or use the included stickers to categorize your items. They stand up pretty well on their own, but if you want them super secure, you can add 3M adhesive (sold separately). Just a heads up - they're not recommended for medical warehouses but work great for clothing storage, retail shops, supermarkets, and offices. The flexibility of the PVC means they won't crack or break when adjusting them. They're reusable too - just wipe clean and reposition as needed. Perfect for teachers organizing classroom libraries, store owners keeping products sorted, or anyone who wants to bring some order to their shelves. The package comes with 20 dividers, which is enough to organize multiple shelves or a whole classroom library. They help prevent books from falling over and make finding what you need so much easier. Definitely a simple but effective solution for anyone battling shelf chaos!