AnglePro 4-in-1 Digital Throw/Incidence Meter Key Features: Allows for easy adjustment of control throws, incidence attachment allows precise digital measurement of wing, tail and thrust angles. Clips to most control surfaces. Resets to zero at any angle—no need to level the airplane. Hold function allows the last reading to be stored. 18-inch bar included (36-inch bar sold separately). Also works as a precision level. Patented technology works on models of all types and sizes. Our Hangar 9 patented Angle Pro can measure precisely to 1/10 of a degree and displays the angle clearly on its easy-to-read digital screen. Measure exact elevator, aileron and rudder throws, and compare wing and tail incidence quickly and easily. The meter can be "zeroed" at any angle, so the airplane doesn't have to be level in order to measure.