Ballpoint Pens
Ballpoint pens are writing implements for writing characters and symbols on paper media. They have a small ball at the tip to which the internal ink adheres by rotation. Pressing the protrusion on the top of the ballpoint pen reveals the tip, and pressing it again retracts it inside. There are two main types of ink, oil-based and water-based. There are various features, such as a type that integrate multiple ink colors, a type that has superior quick drying, and a type that has low friction and feels light to write with. The ballpoint pen called Frixion has ink that becomes colorless at high temperatures, which allows content to be erased after being written, but this should not be used for documents or addresses that must not be erased. Most ballpoint pens have fixing clips, and models where these are movable can have even thick objects inserted.