I have this on my 500 series heli and it works perfect as a tail servo. It is high speed on low voltage (4.8v). helps the gyro hold the tail rock solid. Just remember to run a voltage regulator to your gyro or if your gyro is able to handle higher voltage run the regulator to your servo. Most gyros don't like anything over 5 volts. Great value, definately recommend this for a tail servo.