The Scale rules 2030 with L:300mm is an electronic part manufactured by MEDID. It is an electronic ruler with a maximum length of 300mm, or 12 inches. The ruler consists of a plastic or aluminum carpenter's scale, marked with a millimeter scale which is composed of single graduations of 2mm. On the opposite side, the scale has a ruler with single graduations of 1/8-inch. The ruler also has an automatic on/off switch, so that when measuring with the ruler, the scale will light up automatically. The main feature of the Scale rules 2030 is its ability to measure accurately even in the dark. It is powered by two AAA batteries. The accuracy of the ruler has been certified to be 0.02mm.