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 Eastern Bloc increased from 10% to 30%, from 1950 to 1990, with the Soviet Union being the world's largest producer during the mid-1970s and the 1980s, and China starting major lead production in the late 20th century. Unlike the European communist countries, China was largely unindustrialized by the mid-20th century; in 2004, China surpassed Australia as the largest producer of lead. As was the case during European industrialization, lead has had a negative effect on health in China. Production of lead is increasing worldwide due to its use in lead–acid batteries. There are two major categories of production: primary from