COBRA 8 6S MAX ESCOverview Introducing the Cobra 8, Castle's next generation electronic speed controller for surface applications. As the inaugural product in a new line, the Cobra 8 is engineered with cutting edge technology tailored specifically for 1: 8th scale vehicles weighing up to 6. 8Kg (15 lbs). Note: The Cobra 8 ESC is not intended for drag racing applications. The Cobra 8 boasts a state of the art 32 bit, dual core processor, ushering in a new era of