A flexible cover for Diabetic insulin vials. With this measuring device digital signals can be produced at discrete points in time occurring in a periodic sequence by means of a positional determination of one or more identifiable points which are located on a moved surface and within a two dimensional measuring window of the measuring device. The energy storage circuit includes a switch operated by the switch control circuit. A provider data rating is generated from the performance update. In some approaches the conversion includes propagation of electromagnetic waves within an indefinite electromagnetic medium, and the indefinite medium may include an artificially-structured material such as a layered structure or other metamaterial. Each pair of composite frames are opened and closed quickly and easily, by the user, for frequent changes of displayed material.