HS-5645MG Digital High Torque Ball Bearing Metal Gear Standard Servo from Hitec - HRC35645S
The digital version of Hitec's popular 645 is the HS-5645MG, featuring a programmable digital circuit and their custom MP\/metal gear train technology. Perfect for larger airplanes and heli’s, the HS-5645MG will deliver higher resolution and torque than its analog brother.
Features:

EPA, speed, direction, and fail-safe programmable (see tech note)
MOSFET amplifier
Gold plated contacts
Three metal gears
Dual ball bearings
Indirect drive long life potentiometer
High standing torque
Watertight and dustproof
Works with fixed winged aircraft and helicopters up to 40 pounds

Includes:

1x HS-5645MG digital high torque ball bearing metal gear standard servo
1x white small X-shaped servo horn
1x red Large X-shaped servo horn
1x white adjustable servo horn
1x white off-set straight servo horn
1x white disc servo horn
1x blue aluminum, heat-treated servo arm horn
4x 2 x 14mm mounting screws
4x brass eyelets
4x black rubber vibration isolators

Tech Note: In order to program the Fail-Safe on this servo you will need to purchase the Hitec field programmer sold separately. The metal servo horn will fit any Hitec servos that have a "+" stamped on top of the output shaft.