The Fiber Optic Cable Marker is designed to visibly identify fiber optic cable at a wood utility pole or other structure. Bright orange color is easily identifiable. Indoor & outdoor fiber cable high visibility markers, id labels, printers, warning signs & posts, cable id sleeves and more for fiber optic applications. Misidentification can cause downtime, disrupt essential services, and create safety hazards in data centers. Heat-shrink tubing labels are ideal for outdoor installation or in difficult conditions. 1 When they are applied using the help of a heat gun, they adhere permanently to the jacket of the cable and.