Specifications: 1.Width*Length: 35*50mm 2.Weight: 13.8g Wiring method: 1.7.4V lithium battery charging terminal can be directly inserted in the white terminal; 2.Connect the power supply to the blue terminal , the positive voltage can be 5~8.4V . Usage method: 1.Connect the power supply to the board; 2.Connect the servo to the servo interface. "+"is positive, "-" is negative, "S" is the signal terminal; 3.Turning the knob, the servo will rotate synchronously; 4.There is an elastic button under the knob which can switch mode; "Back to" is: back to the middle position; "Manual" is: knob control. Package included: 1x Servo Tester