Futaba S9257 EP Heli Digital Servo FEATURES: For use with the Futaba GY401 (FUTM0807, FUTM0808) and the GY502 gyros Equipped with two ball bearings One year limited warranty INCLUDES: Futaba S9257 High Speed Digital Servo with .83 (21mm) diameter round horn, 1.5 (39mm) diameter four-point horn REQUIRES: Connecting to gyro