Power HD High-Torque Digital Servo HD-9150MG

via Pololu
$75.08
SKU PL-1048

The HD-9150MG is a great high-quality, standard-size servo that features digital electronics for improved performance and all metal gears with two ball bearings for the delivery of a tremendous amount of torque. The lead is terminated with a standard “JR”-style connector, which is Futaba-compatible. The pictures below show the servo’s gear train and an example of the hardware that might be included with this servo (hardware might vary).

You can find more information about this servo under the specifications tab and in its datasheet (425k pdf).

Note that, as with most hobby servos, stalling or back-driving this servo can strip its gears.