OSE Parallel Harness with 8-gauge wire for use with EC8 bullet connectors. Using this will allow two batteries to double the system's MAH, but the voltage will remain the same. Includes:Everything in the picture.8 Gauge Wire soldered to the EC8 connectors. Note:Because the runtime is doubled, it's important to monitor heat buildup in the motor, ESC, and batteries. You must use two battery packs with the exact same specifications, age, and quality. Failure to do so could cause a fire.