The PowerTome is the only fully upgradeable ultramicrotome, with the ability to take a PTXL, the routine workhorse, and build it up to the PTPCZ research level system with computer control and HD video options. The customer has the choice of upgrading to a PC based controller with or without the high-definition video package. The PTXL is controlled via a digital tactile controller, eminently suitable for routine work. The PowerTome is capable of accommodating glass knives up to 12mm wide, triangular tungsten carbide knives, and any commercial brand of diamond knife. The PTXL can be upgraded to the PTPC, PTPCZ, and PT3D for use with a computer based controller with HD video options. Various add-on components for array tomography and cryo applications are also available.