Leica M520 Surgical Microscope; a surgical microscope with a 6:1 motorized zoom magnification, 207-470 mm motorized Multi-Foc variable objective lens with diameter and light intensity of illuminated field continuously adjustable and high power 300W xenon lamp (both main and back-up illimuniation) through fiber optic cable; Leica Microsystems (Schweiz) AG, Business Unit SOM, Max Schmidheiny-Strasse 201, CH-9435 Heerbrugg, Switzerland; Leica Microsystems Inc., 90 Boroline Road, Allendale, NJ 07401; Leica Microsystems Inc., 2345 Waukegan Road, Bannockburn, IL 60015-9792 The M520 microscope was sold with the following floor stands to form Leica Surgical Microscope Systems: a) MS-1 floor stand with manual balancing for the microscope carrier in three axes and three electromagnetic and mechanical brakes; b) MS-2 floor stand with 3 step balancing for the optical head, autobalance for the floor stand and six electromagnetic brakes; c) MS-3 floor stand with semi-automatic balancing system and six electromagnetic permanent magnetic brakes, cantilever range: 1456 mm d) ) OHS1 floor stand with semi-automatic balancing system and six electromagnetic permanent magnetic brakes, e) OH3 floor stand with fully-automatic balancing system and six electromagnetic permanent magnetic brakes, cantilever range: Max. 1520 mm f) F40 floor stand with continuously adjustable balancing system and four electromagnetic permanent magnetic brakes, Maximum reach 1496 mm