The fiber optic bundle transmits the video and photos taken on the sea floor back to the scientists on the ship. There are three optical fibers--one carries video and photo information, another carries data information gathered by the instruments on the ROV, and the third is a spare. Copper wire bundles, surrounding the fiber optics, carry electricity to the instruments on the ROV. The visible yellow coating is a protective jacket, while the pink material provides some flotation and additional protection from chaffing.