1. Synchronizes the output of the servo system and servo control output signals for precise control of servo performance. 2. Tests subtle changes between different servos. (1 millisecond = 1000 microseconds) Operating Voltage: 4.8-6.0V Dimensions: 75x38x15mm Weight: 26.2g Signal Width: 800-2200µs 1. 50H analog servo signal cycle, 20µs, frequency, 50Hz 2. 125H digital servo signal cycle, 8µs, frequency, 125Hz 3. 250H digital servo signal cycle, 4µs, frequency, 250Hz Instructions: Automatically enters manual mode upon power-up. Turn the potentiometer to increase or decrease the signal width. Press select again to select between center and automatic modes. Press PW to select a pulse width between 125H and 250H. Warning: Digital or analog signals should be adjusted using the corresponding servo system settings before plugging into the steering servo to avoid damaging the servo. Signal lines (+ and -) from top to bottom. Color:Black & Blue Material:plastic Package Contents: 1 * RC Servo Tester