There are 3 modes to check servos or ESC: Manual mode: turn the knob with different speed, check the reaction time; Neutral mode: make the servo go back to the neutral ; Automatic "window wiper" mode: make the servo swing like a window wipers in the biggest angle. It can 1-3 servos simultaneously and test such as 1-3 servos consistency and so on. You can also 1-3 ESC to test and compare their reaction time respectively. It can 3 servos of the CCPM helicopters and select servos. It can also the servo of airplanes install the steering-box and adjust planes by using such as the neutral mode and so on. CCPM Servo Consistency Master/Servo tester. The device also can be used as a signal generator for electric speed controller (ESC). With it, you can test your motor system without using a transmitter and receiver Package Contents: 1x tester 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.