The two acute angles of the isosceles square are 45 °. Two identical isosceles right triangle rulers can form a square or a larger isosceles right triangle. The two right-angle sides of an isosceles square are equal in length.

The ruler should not be mixed with a knife or metal stationery. When mixed with a pen, the pen cover must be put on. The ruler has sharp parts. Pay attention when using it to avoid scratching. Be sure to prevent exposure to the sun and long-term sunshine, and keep away from kindling, so as not to affect the accuracy of the measuring instrument and cause danger. It is better not to clean the ruler with a brush.