These ultra-microtomes are designed to cut plastic embedded specimens (e.g. biological tissues, polymers) into very thin slices (sections) required for examination in a transmission electron microscope (TEM).  The Ultramicrotome on top is a brand new RMC.  The one on the bottom is a fairly new Leica UC7 on loan from Wood Science.   Sections made with these tools are only a few nanometers thick and are cut by special glass or (expensive) diamond knives.