The size distribution and the shape of the carbon particles determines the efficiency and throughput of the filter. Especially the amount of fine particles (< 1 mm) is a critical parameter as the fines might block the filter. Sieve analysis is most commonly used for particle sizing of activated carbon, however, this method has some disadvantages. On the one hand, sieving raises dust through abrasion so that the measurement process modifies the original size distribution of the sample. On the other hand, sieving does not allow for shape analysis. If, however, products like carbon rods are to be analyzed, it is essential to determine the length and diameter of the rods precisely and with a high statistical security.