Marker pen
A marker pen or "marker" is a kind of writing implement similar to a pen but never having an external ink-source; the tip is typically made of felt and when this is true it can also be called a felt-tipped pen. Magic Marker is a trademarked name for a brand of this, as is Texta, a common name for such a pen (after the brand, akin to Kleenex).
While usually intended for permanent marking, markers can be non-permanent when intended for use on overhead projectors, whiteboards, or sometimes when intended for use by children for ease of cleaning by adults.