Identoline Underground Warning Tape is made out of heavy duty B-720 polyethylene with overcoated graphics to protect the legend from acids, alkalis and other soil substances. Used to identify the location and direction of buried utility lines and pipes. Install below ground level, directly over the line it protects. Tape is 4.0-mil thick with a tough tensile strength of 1750 psi. Uses American Public Works Association (APWA) color coding. Overcoated graphics provide long-lasting legibility and hold color values.