Mechanical pencil leads in a limited range of diameters (0.5 mm, 0.7 mm, or 2 mm) for their own products. Koh-i-Noor makes mechanical colored pencils with replaceable leads in 2.0, 3.15 and 5.6 mm sizes. Mechanical pencil A mechanical pencil (US English) or propelling pencil (UK English), also clutch pencil, is a pencil with a replaceable and mechanically extendable solid pigment core called a "lead" . The lead, often made of graphite, is not bonded to the outer casing, and can be mechanically extended as its point is worn away. Other names include microtip pencil, automatic pencil, drafting pencil, technical pencil, click
Lead smelting the example above) is expelled, and the lead oxide is reduced. Anglesite, Cerussite, Pyromorphite, Mimetite and Wulfenite are other lead ores. Other elements frequently present with lead ores include zinc and silver. Most of the lead produced comes from secondary sources. Lead scrap includes lead-acid batteries, cable coverings, pipes, sheets and lead coated, or terne bearing, metals. Solder, product waste and dross may also be recovered for its small lead content. Most secondary lead is used in batteries. To recover lead from a battery, the battery is broken and the components are classified. The lead containing components are processed in