Aftermarket 6 Pin GY6 AC CDI Ignition NeedleAftermarket 6 Pin GY6 AC CDI Ignition Needle Motorcycle Accessories Engine Parts ATV Motorcycle Scooter GY6 Igniter GY6 50 Cc 125 Cc 150 Cc ATV AC Infinite Speed 6 CDI Ignition Needle The AC CDI is a type of ignition wherein it can be operated without a battery installed on a bike but needing a High Voltage Generator that will charge the capacitor inside the cdi to discharge through your ignition coil producing spark at the spark plug. For GY6 engine