[Ed can't help but watch the dragon out of the corner of his eye- he doesn't have a great history with large animals, so he's still wary.]

You'd be better off asking Winry about that, she can explain it in detail. What I know is that I had a port installed here- [He rests a hand on his shoulder briefly,] And the automail limb connects to that. As long as the nerves still work, the arm moves like it's real.