Tractor reciever, Implement reciever running RTK and an I-grade controller that is interchangeable between anything newer than a 8X20 or 9X20 series tractor.  The I-grade controller is now the same controller used for implement steering.  We started out using and quick survey base in the field but now we just run off the dealers RTK network. You'll also need a SWPro+ unlock if you want to do automatic control.