This is the Hitec HS-645MG High-Torque Metal-Geared Universal Servo
These metal-geared high-torque servos work great for steering servos
The connector is universal, so it will work with JR, Hitec, Futaba,
and current Airtronics radio systems
This servo puts out 133 oz/in of torque at 6 volts
This is great for cars, trucks, boats, and airplanes.
Unbreakable MP Gear
The heart of the unbreakable geartrain is the MP Gear
The MP Gear is made utilizing a revolutionary production technique
that injects a high impact plastic around a metal pinion gear to form an
unbreakable first gear
By utilizing this gear Hitec has succesfully reduced the amount of drive train noise that is common in metal gear servos and at the same time added considerable
strength to the geartrain.
Three metal gears.
Dual ball bearings.
Metal 1st Gear
Four adjustable splined horns
For use with .60 size helicopters, gas or electric cars and boats
FEATURES:
Three metal gears.
Dual ball bearings.
Metal 1st Gear.
Four adjustable splined horns.
For use with .60 size helicopters, gas or electric cars, trucks, and boats
INCLUDES:

One ultra torque servo with 11.5" connector wire.
One white small X-shaped servo horn.
One red Large X-shaped servo horn.
One white adjustable servo horn.
One white off-set straight servo horn.
Four 2 x 14mm mounting screws
Four brass eyelets
Four black rubber vibration isolators
SPECS:

Speed: 0.24 sec/60 degrees at 4.8V
0.20 sec/60 degrees at 6.0V
Torque: 106.93 oz/in at 4.8V and 133.31 oz/in at 6.0V
Length: 1.59"
Width: 0.77"
Height: 1.48"