This is a rare Wisner Plasmat casket set.  This set is designated for the 5x7 format, but it can just as well be used for 4x5, and many focal lengths will cover 8x10 (see chart on top of box). There are five lens cells: 250, 350, 400, 450, 500.  They are used singly or in combination to form 13 focal lengths.  A Copal 1 shutter is included.  The shutter’s millimeter markings correspond to the information on top of the box to set the aperture.  The shutter and lens elements are all in fine condition.