Mechanical pencil is made entirely of wood except for the spring, and the structure is an original by RINKUL. Made from natural materials, thus the shade and grain will be unique to each product. Refill lead size: 0.5mm The nib is made of ebony, maple, or oak. Our products are entirely made from wood, including the smallest parts, using our own precise NC machines. We use the natural color and texture of the wood, making our products safe for people with allergies. Each item is finished with Watco oil, mainly made from linseed oil, and our homemade beeswax. Every piece is unique. If parts become stiff, apply beeswax cream, furniture wax, or even lip balm, then wipe it off right away.