Counting chamber, Improved Neubauer / Hecht, Karl / Assistent

With double ruling. Calibratable. Cell depth 0.1 mm. Same ruling as Improved Neubauer, but the large square in the centre is divided into 16 squares each with a side length of 0.25 mm. Unlike the more modern Improved Neubauer counting chambers, the counting area of each group square is limited by the outermost of the triple border lines.