Test : can be synchronized output control 4 servos. Test: used to compare the performance steering control of the steering servo output signal can be to 2us (1 milliseconds = 1000 microseconds), you can test the steering is able to respond to subtle changes. PPM Signal: with PPM signal test function in the display, the input PPM signal changes while the input the PPM signal synchronization output to the servo Energized automatically enter manual mode (Manual) 20us 50H analog servo signal cycle, frequency 50Hz. Adjustable: potentiometers to decrease or increase the width of the output . 3 Modes:S-1 manual mode (Manual)/S-2-bit mode (Neutral)/S-3 automatic mode (Automatic) Mini 3 Modes Digital Servo/ESC Consistency Tester Steering Measurement for RC Helicopter Airplane Car Tool Steering tester 1.This Digital Servo Tester is with high accuracy. 2.You can test control 4 servos at the time and change the test modes as you need. 3.With potentiometers, you can decrease or increase the width of the output . colour:black Material:ABS size:40*75*25MM Package Contents: 1* servo tester Notice: Carefully read the before any , if you are a beginner, it/'s advisable to be assisted by an experienced adult. Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.