The goal, when adhering to skin, is to hold the device in place until it is time to remove it and to not damage the skin, either during wear or at the time of removal. Using methods developed for determining the surface energy of plastics and other materials, the surface energy for human skin has been measured in the low twenties [dynes/cm] – in other words, skin is as difficult to stick to as untreated polyolefins or even fluoropolymers. Low surface energy, as a property of human skin, is generally great for most of the things skin is expected to do, such as easy removal of contaminants with simple soap and water. The downside is that tapes must balance between adequate adhesion levels for the majority of users – the middle of the bell curve – and the ends of that curve. When the adhesion is too low, the device may not stay in place long enough for the full therapeutic effect and if it adheres too well, the tape may cause some mechanical trauma at removal.