Label printer ribbons are usually contained inside a cartridge which is then inserted into a label printer. Most label printer ribbons are thermal transfer printer ribbons. Thermal transfer printer ribbons are heat sensitive and melt when in contact with the thermal printhead inside the printer. This causes the ink on the ribbon to transfer onto the label forming a durable and crisp image. Label printer ribbons are available in several different colours and are for use with a wide range of label printer models.