Sovereign as long as they work. After 10 months they stopped charging, blinked white and red and refused to start. Went in and took out a couple of new ones on the warranty. Unpack them from the carton at home and it is the same, do not start, do not load. May go in again and change again. Tests for safety directly when I come out of the store. Does not start, does not load. Got the money back and are now looking for other kids.