Durable ProtractorDigital goniometer made of carbon fiber and ABS, wear-resistant, not easy to deform, will not scratch your hands, lightweight and durable, easy to carry. Large LCD DisplayThis digital goniometer is equipped with a larger LCD display for clearer and faster readings. High PrecisionThe accuracy of this goniometer is 0.1 degrees, resolution 0.05, measuring range: 0-999.9, folded length: 7.9 inches/200mm, total length: 15.7 inches/400mm. NOTE: You need to level the ruler and reset the value to zero before measuring the angle. Otherwise, measurements will be inaccurate. [Instructions for use] Short press the Hold/Rev button to hold the data; long press the Hold/Rev button to reverse the display. This function is more convenient for large-angle measurement and reverse measurement. Short press the zero button, the value will reset to zero at any angle for higher precision, it will automatically shut off after 6 minutes of inactivity.