Having the servo mounted in the gearbox isolates the load to a steel hub-shaft that is supported in a pair of ball bearings to protect the servo from any axial loads. The gearbox opens up a world of mounting possibilities given the M4 threaded holes on each side which are on the grid pattern for compatibility throughout the goBILDA® system. The hub on the top of the gearbox provides threaded holes to fasten to, but you can also opt to fasten straight to the aluminum output gear using M4 hardware and standoffs or spacers. The 8mm REX bore of the hub-shaft can drive an 8mm REX shaft or act as a wire pass-thru.
If you’re not accustomed to using a servo gearbox, it’s just like a normal servo only larger. While the range and torque might be greater than the servos you’re used to, the control signal is identical. It will simply plug into an R/C receiver, an Arduino, Raspberry Pi, or REV controller. Furthermore, since the servo hasn’t been modified in any way, it is FTC legal!