This is the Futaba S9257 High Speed Digital Servo for Helicopter Gyro Operation.

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, 1.2" (32mm) diameter six-point horn, mounting hardware, digital servo precaution sheet and warranty card

REQUIRES:
Connecting to gyro

SPECS:
Dimensions: 1.4 x 0.6 x 1.1" (36 x 15 x 29mm)
Weight: 0.92oz (26g)
Torque: 28 oz-in (2.0 kg-cm) at 4.8V
Operating Speed: 0.08 sec/60¢X at 4.8V
Lead Length: 7.9" (200mm)

COMMENTS:
For use only with FM, PCM and HRS systems. Do not use with AM systems