on this one when you pull the elevators off the fuse, if you stood the elevator on its end and looked down into the end that meets the fuse you see a square cut out that you slide your servo into. and when you lay the elevator back down like you were going to mount it back on the plane, now the servo is laying on its side with the servo arm poking out of a hole cut out on the bottom of the wing. to turn the arm 180 it would now be poking out of the top of the elevator.