A marker pen, fine liner, marking pen, felt-tip pen, felt pen, flow marker, sign pen, vivid, flomaster, texta, sketch pen, koki or simply marker is a pen which has its own ink source and a tip made of porous, pressed fibers such as felt. A marker pen consists of a container and a core of an absorbent material that holds the ink. The upper part of the marker contains the nib that was made in earlier times of a hard felt material, and a cap to prevent the marker from drying out.