Writing implements are tools used to create written works. The most common writing implements are pencils, pens, styluses, fountain pens, and ballpoint pens. Pencils are made of graphite and clay and have a wooden casing. Pens are usually made of plastic and have a metal tip that contains ink. Styluses are similar to pens but have a rubber or plastic tip instead of a metal one. Fountain pens contain a reservoir of ink that is fed to the nib through a feeder. Ballpoint pens have a small ball at the tip that rolls over the paper, transferring ink from the reservoir.