The HD-1501MG is a great high-quality, standard-size servo that features metal gears and two ball bearings and can deliver a tremendous amount of torque for a servo this fast. The lead is terminated with a standard “JR”-style connector, which is Futaba-compatible. The picture below shows an example of the hardware that might be included with this servo (actual hardware might vary).
The pictures below show the metal gear train and ball bearings that help the servo deliver such high torque.
Note that, as with most hobby servos, stalling or back-driving this servo can strip its gears.