Nature line notebook convertible into a smartphone holder, made from recycled milk cartons. It features a hard cover with bamboo detail on the front cover, a matching fabric bookmark and elastic band, and a pen holder. The inside contains 100 sheets with a single-stripe layout, and the back cover showcases the distinctive design of recycled milk cartons. The use of milk cartons, which are primarily composed of cardboard and aluminum, contributes to the circular economy by recycling and repurposing different packaging materials. This notebook is lightweight, resistant, and customizable.