A Japanese bamboo slide rule for electrical engineers. The rule has several scales of numbers in the center. There is a movable ruler. The inner ruler is moved and placed so that the value on it is opposite the value with which it needs to be calculated. There is a transparent window on the rule that moves to the right or left when the red stripe of the window is placed opposite the values ​​we have chosen and we get the result without dots. The user must determine where the decimal point is. The rule does not calculate + or - .