The ratio between the actual irregularity present in the material and the calculated limit irregularity is called index of irregularity. It is denoted by I. Accordingly the best yarn have a value of I = 1. Thus, the higher value of I indicate that the yarn is more irregular. On the other hand, the CV of the most regular/uniform strand of material in which the ﬁber ends are laid in a random order in the sliver, roving, or yarn is called limit irregularity.