ESKY Multi Servo ECS speed controler tester checker RC Car Heli Boat Plane .Test device can easily detect the clearance, jitter and median of all kinds of Servo (server) It can easily connect the ESC and test the working status of the ESC or Motor It can connect three sets of servo or ESC at the same time, use SCM to control with Good stability, high accuracy Power Supply:4-5 pcs of #5 battery,ESC built-in BEC or UBEC TO Provides power to the tester.When you use the ESC with built-in BEC,No additional power supply need,connect the servo or ESC that you want to test to begin testing. Manual pulse width adjustment