Superior MaterialAdjustable multifunctional ruler is sturdy and durable. The ruler is made of high quality stainless steel and the corner bracket is made of zinc alloy, which ensures that it will not rust, deform or break easily High AccuracyMeasuring range is 0-300mm, double-sided ruler in metric and inch graduations for easy and accurate reading. At the same time, it combines a level bubble, accurately measure balance to improve work efficiency Multi-functional measurementThis ruler can measure a variety of data, such as right angle , 45 angle, length, depth and width. Come with a built-in scriber that makes it easy to mark without a pen Adjustable DesignSpring-loaded screw and efficient clamping system make it easy to remove and install the stainless steel ruler, and the ruler smooth also facilitates sliding measurement Widely UsedThis ruler is suitable for measuring, marking, etc., to help you measure accurately. It is widely used in home, engineering measurement, housing construction and other places NoteIn order to achieve a more accurate right angle, the end of the ruler in steel cannot be pressed against the rib (about 15mm) How to know if it is a right angleStep 1: Draw a vertical line on a sheet of white paper (for example the handle to the right). 2nd step : Reverse the square and draw another vertical line on the first vertical line (so the handle to the left). Step 3: If the two vertical lines coincide perfectly, i.e. the angle of the square is a right angle