Battery pack works, it's a battery pack. LOL Extends the recording time about an hour or so depending on if the wifi is on or not.
Needed this to boost the record time for a track day event where charging in between sessions would be limited. Totally forgot to order until just a few days from the event. Backcountry had a great price and even with expidited shipping it was not more than many other places I looked with regular shipping. Box was shipped and arrived just when they said it would, got it in plenty of time for my track day.