This professional-quality Rotring Hi-Polymer lead features an extra-strong formula designed to resist breakage during use. The HB hardness grade balances precision with smooth writing, making it versatile for sketching, technical drawing, writing, and detailed work. Each refill pack contains 12 pieces of 0.7 mm lead—the ideal diameter for mechanical pencils requiring fine, controlled lines. Perfect for architects, engineers, artists, and anyone who demands reliable performance from their drafting tools.