A ruler, sometimes called a rule or line gauge, is a device used in geometry, technical drawing, engineering and building to rule straight lines. [1] Engineering designers used (before the advent of CAD) devices with graduations marked on their edge called scales, when setting out or measuring length on a drawing. They did not draw lines with their scales; they used to set or T-squares when ruling a line.

These rulers have the same tolerance and the same finish as above, but without the tap drill table on the back. They do have the mm-inch table. These rulers have a raised edge on the right-hand side to make picking it up from a flat surface easy. The 15 cm and 30 cm rulers will lift up all the way; the 60 cm and 100 cm rulers only lift halfway up. Steel rulers also feature easy to read extra-large numbers and read even larger numbers for the decimals.