Thoma counting chamber, counter grating with 5 large squares, 1 unit(s)Thoma counting chamber, counter grating with 5 large squares Material: glass. For thrombocyte and erythrocyte counting. 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. Small square: 0. 0025 mm2 The counting grid appears under the microscope as a grid of dark lines. In vitro diagnostic medical