ON RULER is a helpful measuring tool for quick measure of small object's length. It helps you to measure the dimension of objects conveniently and accurately with your phone at anytime and anywhere. It combines two important ruler measuring modes in one app, which is 2-Lines Ruler and 4-Lines Ruler. You can also switch the ruler's length unit between millimeter and inch by a click. ON Ruler is smart and easy to use. You can measure the length and width of any objects that in the range of your screen size by simply place it on the device's screen and move the line limiters one after another. The dimensions of the object (width, length and area) will shows on the screen automatically. To measure objects that larger than your device's screen size, you can use ON Measuring Tape, ON-2D Camera Measure or ON-3D Camera Measure (Free measuring tools). For perfect accuracy, you will be requested to do calibration at the first time you open the application. Calibration need to be carried out only

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