BLAUBRAND®. Double ruling. Without snap-on clips. Cell depth 0.2 mm. The ruling is rectangular, covering an area of 5 mm2. The large rectangles measure 0.25 x 0.20 = 0.05 mm2. They are each subdivided into 20 mini squares with an area of 0.0025 mm2. This chamber is commonly used for counting cells in the cerebrospinal fluid, or for counting nematodes.