Note: The color of the item may vary slightly due to photography and your own computer1.This is THE BEST 30A ESC for multirotor2.This hardware, with the SimonK firmware, gives you the perfect solution for multirotor use:3.Highest efficiencyHighest accuracy with Crystal Oscillator (Temperature won't affect the PWM operating range like other cheap ESC's).No low voltage cutoff, because any cutoff in a multirotor = crash.No over temp cutoff, because any cutoff in a multirotor = crash.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).Super simple, foolproof operation Nothing to program other than the throttle.Can be used with the replacement for pixhawk flight controller with the appropriate motors.4.Calibration operation method: first push the left throttle stick to the highest position, and then power on the drone. First, you will hear the sound of dripping, then immediately put the throttle stick to the lowest position, and then it will emit dripping, dripping The sound indicates that the calibration is complete, and finally the wiring is restored.ESC SpecificationsCont. current:30AMax. current: 35AInput Voltage: 2-4S /4-12 cell Ni-MH/Ni-CdBEC: 5V 2A(Linear mode)length 145mm including power cableSize: 55x26x8mm/2.2x1.02x0.31InchWeight:91gPackage included:4 x 30A RC Cars Brushless ESC