The Hamilton 666 has directly driven minutes and indirectly driven seconds. The centre wheel is below the level of the micro-rotor.
The 2 small wheel visible on the left under where the micro-rotor used to be are reversers.
The movement has a double ratchet wheel so that the automatic system can wind the mainspring without it affecting the crown wheel. The bottom ratchet wheel, with the 4 round holes, can turn and the top ratchet wheel will stay stationary. When the crown is used to wind the watch, however, the protrusion from the top ratchet wheel will go into one of the round holes of the bottom ratchet wheel and make it turn.
The centre wheel is driven directly by the mainspring barrel, whereas the seconds pinion is driven by the third wheel.
