A dual stage current limiting surge protector system for protecting telecommunications equipment from power and surge transients is provided. One such system utilizes one or more electrodes to measure an additional analyte. Similarly, the second lens carriage is positioned within the optics barrel so that there is a second optical path through the lens in the second lens carriage to the second image sensor section. The front edge is located outside the quadrilateral, and the rear edge is located inside the quadrilateral.