Andoer RCD3060 Mini OSD Dual Voltage Monitoring System for RC Multirotor Quadcopter Helicopter FPV It can check two voltages and overlap them onto the video signal. Factory calibration, its precision reaches +/- 0.1V The background is light dark when the data is displaying in overlapping way, this can ensure customers read clearly and precisely under strong light environment or the light dark background. 40 position data modes are for choice. (We can change the mode numbers and the displaying position according to the request of our customer) It can automatically record the last displaying position and wont be lost even the power is off. LED light will flash when no video signal is received