One of the most common measure of the quality of a fabric is the number of threads per unit length in both the warp and weft directions, or its picks and ends.
Picks and ends of any fabric are normally determined with the help of an ordinary counting glass having a square or rectangular opening of specified size. However, when a greater degree of accuracy in determination of picks or ends is needed, or the weave is too fine to be checked with an ordinary counting glass, this counting is carried out with the help of a traverse thread counter.
In this apparatus a traveling microscope is used for viewing the weave of the fabric under test. Openings of known widths are provided to enable picks and ends per unit length to be determined, both in metric and imperial systems.