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 4.8~5.5VOutput signal width: 800~2200usButton 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: 50Hz2. 125H digital the steering gear a signal cycle: 8us, frequency: 125Hz3. 250H Digital Servo signal cycle: 4us, frequency: 250HzNotice:Carefully read the instruction before any use, if you are a beginner, its advisable to be assisted by an experienced adult.colour: blueMaterial: composite materialSize: 75 x 38x 15mmPackage Contents:1 x Digital Servo/ESC TesterOnly the above package content, other products are not included.Note: Light shooting 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.