The length of the strings or stagnates is such that: the least obscured place of the rug is chosen, and the length of the pin is measured from the end of the node to its free tip, called the length of the node. This measurement is made by a metallic and narrow scale, which is meant to be constructed and carried out vertically without Perezs, acting as it puts the scale and size between the two rows of nodes after ensuring that the end is woven into the field of rugs. If the carpet varies according to its plan in different parts of the nodes, they determine the length of the node in each section. To make precise measurements, they do it at least 10 times per length. The measurement unit is millimeter.