30A ESC OPTO 2-4S BLHeli Brushless Electronic Speed Controller for QAV250 Racer 250 ZMR250 F330 F450 FPV Racing Quadcopter Drone

Features:
Compact, lightweight and high performance speed controller.
This is THE BEST 30A ESC for multirotor.
This hardware, with the BLHeli firmware, gives you the perfect solution for multirotor use.
Highest efficiency design.
Highest 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 high response rate.
Super simple, easy operation!