A photometric apparatus which satisfies the demands for reductions in the size, thickness and cost and which is highly optioned despite a simple arrangement. A second clasp is mounted to a retractable cable connected to a constant tension cable reel mounted within the casing: The cable is payed out of and retracted into the bottom of the housing in its normal use position, and the second clasp is attached to a fixed support or \u201clock point\u201d located below the normal working height of the tool. The contact pH of the treated carbon remains within the potable pH range for treatment of more than 100 bed volumes. Spacer panels are connected between three of the four total side, front and rear panels. The foldable map stand apparatus can be folded into a more collapsed form so that it may be stored in a more convenient location within the automobile when the map holder is not in use.