Because of the numerous changes made during recent years in the designations of welded wire fabric, some tips may be in order on how to specify and order it for use in reinforcing concrete. In 1970, the American Society for Testing and Materials changed from the gage system to a numbering system designed to simply use of wire fabrics in concrete design. The more rational numbering system relates to the cross-sectional area of the wire and involves a letter-number combination. "W" designates smooth wire and "D" designates deformed wire. The number following the letter gives the cross-sectional area of the wire in hundredths of a square inch. This system makes it easy for the designer. For example, if a steel cross-sectional area of .15 square inch per lineal foot is needed, it can be met with W5.0 wires on 4 inch centers (3 wires per lineal foot, each with a cross-sectional area of .05 square inch. Welded wire fabric is designated by two numbers and two letter number combinations. An example is 6 by 8- W8.0 by W 4.0. the first number gives the spacing in inches of the longitudinal wires, the second gives the spacing of the transverse wires. The first letter-number combination gives the type and size of the longitudinal wire, the second designates the transverse wire. Thus, in the example the longitudinal worries are 6 inches apart and the transverse wires are 8 inches apart. The wires are smooth and the cross-sectional areas are.08 square inch in the longitudinal direction and .04 square inch transversely. Table I found in the article compares the new designations to the old gage designations for the common stock sizes of welded wire fabric.