Arched Ruler / Arched Ruler

When used to draw, the edge of the ruler is sometimes stained by the ink on the pen tip. The paper will be polluted when the ruler moves, which causes abandonment to the nearly completed paper and gives you a headache. Furthermore, it is uneasy to pick up the ruler from the desk, which causes another problem. Therefore , we designed the ruler again —— shaped vaulted ,it has several advantages .