Stock setup is 4S. But drop in a 6S pack and it turns into an animal.   

Something this cheap should not be this fun.

@dominicm,
Sir,
Inspired to try 4s on my 3s RareBear (looks about the same size)
Too old to have the courage to put in 2 1000mah 3s lipos in series.
Each of your videos sets off a wonderful new train of thought...
Regards.