This is a 3d printable basic 12in ruler. -Folds into a small pocket sized version -Easy to use -only goes to the 1/8 I personally recommend coloring in the groves with sharpie or with some sort of marker to allow your self to see the distances better

Warning Some people may have trouble printing because it is set very small its a small glitch that makes programs think inches are millimeters just set the scale to 2540% for full size