This aluminum straight edge is an economical alternative to other much more expensive straight edges on the market. This straight edge is very helpful to determine machine table flatness and in setting up machines such as jointers and planers and various out feed tables. The straight edge is made from extruded aircraft aluminum and then the reference edge is machined flat to within 0.003" over the entire 50-inch length. The easy-grip cross section is 7/16 inch thick and 1-3/4 inch wide. Finish is black anodized. There is a hanging hole in one end. These straight edges are available in five different lengths.