Retractable Ballpoint Pens

A ballpoint pen is a writing instrument with an internal ink reservoir and a sphere for a point. Believe it or not the ball point pen hasn't been around that many years and only since about the 1940's had one that became a standard member of our pen community. The internal chamber is filled with a viscous ink that is dispensed at its tip during use by the rolling action of a small sphere. The sphere, usually from 0.5 mm to 1.2 mm in diameter, may be made of brass, steel, tungsten carbide, or any durable, hard (nondeformable) material.