Thoma new counting chamber, without any lines in the boundary areas, 1 unit(s)Thoma new counting chamber, without any lines in the boundary areas Material: glass. Double counting grid. Counting grid with five large squares (corner fields not implemented). The large square in the centre is split into 16 group squares and these, in turn, are split into 16 small squares. No lines in the intermediate areas. Small square: 0. 0025 mm2 The counting grid appears under the microscope as a grid of dark lines. In vitro diagnostic medical