A mechanical pencil (US English) or a propelling pencil (UK English) is a pencil with a replaceable and mechanically extendable solid pigment core called a "lead" /ˈlɛd/. 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 automatic pencil, drafting pencil, technical pencil, click pencil, clutch pencil, leadholder, pen pencil (Indian English), lead pencil (Bangladeshi English), and pacer (or spacer).