1PC 3CH Digital Servo Tester ESC Checker CCPM Consistency Speed Controler + 2PCS 4 Cell AA Battery Holder Case with 2P JR Connector Terminal for Helicopter Car (HJ Servo Tester)
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
Connect: the battery holder red wire is to connect with "+" of "Input" of the servo tester, and black wire is to connect with "-" of "Input".