The offered Glass Magnifier consists of many very narrow concentric ring-shaped lenses, such that the combination acts as a single lens but is much thinner. It is magnification device that uses a convex lens ( a lens that is thinner at the edges and thicker at the center ) to magnify. A convex or bi-convex lens shape bends light rays inward which in turn creates and enables an enlarged view when looking through the lens. Glass Magnifier is very easy to use.