3M 5558 Contact Indicator Tape, 0.079 Diameter Circles (1 Pack) The ultra thin caliper, 6.0 mils total, is suitable for applications with tight design tolerances. As a water contact indicator/label in handheld or portable electronic devices such as cell phones, PDAs, pagers, MP3 players, game players, CD players, cordless phones, two-way radios, laptops, digital or film cameras, video cameras, etc. This product is designed to withstand heat and humidity aging without giving water indication and it will continue to show indication even after prolonged submersion in water. When water comes in contact with the edges of the product, the color changes from white to red.