Ivory Pleximeter Small ivory pleximeter, or plexor made by Arnold & Sons presented by Dr Geoffrey Bewley in December 1946. The object is presented in its case, lined with dark purple satin and velvet, which opens by pushing the small button. Object's manufacture mark is slightly faded. Object itself consists of a cylindrical stem, with two concentric lines one third of the way down. Both ends flare out to a completely flat surface. One end is slightly bigger than the other. Object is lighweight. 1875-1925