This portable multi ruler is perfect for carrying in a pen case or backpack. It measures 30 cm (11.8 inches) when fully extended, and it folds easily in half when you're ready to stow it away. Its transparent body makes it easy to see what's underneath and line the ruler up perfectly.
This multi ruler can also function as a protractor and a compass. The circular swivel joint between the two arms of the ruler is marked from 0° to 180° in 15° increments, and the ruler snaps into place at each interval. Additionally, each arm has a small hole every 1 cm that is perfectly sized for the tip of a mechanical pencil. You can use the holes to make perfectly spaced dots along a line or swivel the arm while holding the other arm in place to draw an arc.