One 6v NiMh battery with JST connector.
Commonly called a “Hump Pack”
These batteries are labelled 3,000 mAh This may be optimistic and they may prove to be of a lesser value. I just copy the specs I am given.
If you absolutely need 3,000 mAh you may be better off purchasing Panasonic, or similar from elsewhere.
Great for planes, gliders, yachts and cars.