Hobbypower SimonK 30A ESC Brushless Speed Controller BEC 2A for Multirotor Quadcopter 30A SimonK firmware Brushless ESC Soldered with 3pcs 3.5mm gold female plug, very convenient to connect motor. Highest accuracy with Crystal Oscillator (Temperature won't affect the PWM operating range like other cheap ESC's). Super high refresh rate, no buffering of the input signal, resulting in more than 490Hz response rate. 16KHz motor frequency, giving fastest response of the motor, and quietest operation as well (no 8KHz squeal).