The ruling shows 9 large squares of 1 mm2 each. The four large squares in the corners marked 'L' for counting leucocytes are each subdivided into 16 squares with 0.25 mm sides. The large square in the center is subdivided into 16 squares with 0.25 mm sides. Each group square consists of 16 mini squares with 0.05 mm sides, each having an area of 0.0025 mm2. The 5 group squares in the large central square are used for counting thrombocytes and erythrocytes. Contrary to the more advanced Improved Neubauer counting chambers, the counting area of each group square is limited by the outer one of the triple boundary lines.