This is the Kinexsis 1/10 4-Pole 4000Kv ESC/Motor Combo. The Kinexsis brushless systems offer the ultimate solution when searching for an easy and affordable method of stepping up to brushless power. Designed for most 1/10th scale on and off road electric vehicles, this system comes with everything users need to upgrade to brushless power. All systems include a potent 4-pole sensorless brushless motor and 70A waterproof ESC that comes pre-wired with a high-current EC3 connector. The ESC is Ni-MH and Li-Po/Li-Fe compatible and was designed to handle up to a 9 cell Ni-MH pack or 3S Li-Po/Li-Fe.