Features: 4 speed controllers in 1 board only 1 pair of battery wire is needed. Safety arming feature: Regardless the throttle stick position the motor will not spin after battery connected. Throttle calibration function: Throttle range can be calibrated to be compatible with different transmitters. User programmable. Multiple program methods supported: transmitter stick LED Program Card. Very easy to program the ESC at home or at the flying field. Compatible with Lipo battery and NiMH battery. Internal timing can be changed to be suitable for different brushless motors. Full protection: Low voltage cutoff protection / Over-heat protection / Throttle signal loss protection.