An H-shaped moat forms either one or two counting areas, or plateaus. Each plateau features an etched grid or ruling.
The ruled surface is either 0.1mm or 0.2mm below the cover glass, limiting the Volume of 1 Square mm of blood or fluid over a square mm at 0.1cu.mm or 0.2cu.mm respectively.
Contact of the flat, polished cover glass surfaces the cover glass supports produces an exact volume of fluid over the counting area.
The difference in surface tension characteristics between the metallic surface on the chamber and the polished cover glass assures smooth capillarity for precise loading and more even cell distribution.