Cartonius is an online supplier of materials, tools, and accessories for bookbinding, notebook making, and book restoration. Its catalog brings together practical components for both detailed handwork and finished projects, with products selected to support precise, professional-looking results.

Bookbinding supplies include European book headbands, linen and cotton threads, tarlatan and spine-reinforcement materials, decorative Italian papers, and needles and pins. The store also offers Teflon bone folders, including a universal model designed to avoid shine or marks on finished surfaces, as well as a V-shaped sewing cradle with a numbered guide, awl, and adjustable spacer to help position and perforate booklets accurately.

For notebooks, planners, and cases, Cartonius sells flat elastic in a range of colors. Its 6.6 mm European-made elastic is composed of polyester and latex and is described as durable, colorfast, and resistant to losing tension. Other categories include bookbinding material kits, finished products, and 3D-printed items. Cartonius serves makers seeking specialized supplies for crafting, repairing, and enhancing books and notebooks.