Goolsky G.T.POWER Professional Servo Tester for RC Aircraft Helicopter Car Servo High performance-to-price ratio, combined with proprietary test algorithm, which guarantee that the test is fast and stable G.T power tester can be powered by lipo battery through the balance charging wire adaptor or DC power supply. It is both convenient and flexible The rolling menu toolbar makes the operation clear and easy The function setting is easy and practical which covers most parameters that end users need The device is equipped with servo and receiver wires, which makes the measurement operation a lot easier