1.This Digital Servo Tester is with high accuracy. 2.You can test control 4 servos at the same time and change the test modes as you need. 3.With rotary potentiometers, you can decrease or increase the width of the output pulse. = Input voltage: DC 4.8~5.5V Output signal width: 800~2200us Button the Select (Note: the key switch function, circulation patterns) 1. S-1 manual mode (Manual) 2. S-2-bit mode (Neutral) 3. S-3 automatic mode (Automatic) Keys pulse width: 1. 50H analog servo signal cycle: 20us, frequency: 50Hz 2. 125H digital the steering gear a signal cycle: 8us, frequency: 125Hz 3. 250H Digital Servo signal cycle: 4us, frequency: 250Hz Notice: Carefully read the instruction before any use, if you are a beginner, it's advisable to be assisted by an experienced adult. colour: blue Material: composite material Size: 75 x 38x 15mm Package Contents: 1 x Digital Servo/ESC Tester Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.