A sensor and method of use provides for detection of an occlusion in tubing during the administration of solutions to a patient. The fibers in the product are of at least two types, fiber A and fiber B fiber A being made from a bioactive glass, and fiber B being made from a weakly bioactive glass. The pin may have a rotationally non-symmetrical shaft portion to provide different wear surfaces that engage a center link of the section of chain. A local inspection can be made by scanning an image and decoding it with relatively inexpensive tools available on site. At the back end of the head, an electrical terminal is located on the fixed layer and electrically insulated from the upper shield.