Launched in 2020 after about five years of development, the RM 65-01 was described by Richard Mille as its most complicated automatic calibre. It translates a split-seconds motorsport chronograph into a watch intended for regular use. The skeletonised RMAC4 combines hours, minutes, running seconds, date, rattrapante chronograph, twelve-hour and thirty-minute counters, a crown-function selector and rapid winding.
The movement runs at 5 Hz, or 36,000 vibrations per hour, so the chronograph can resolve one-tenth-second intervals. A six-column-wheel split-seconds mechanism controls the overlapping central hands. Colour coding separates functions across an otherwise dense dial: yellow for time, orange for chronograph indications, red for winding, blue for the date and green for the function selector. Pressing the pusher at eight o'clock rapidly charges the barrel when the watch has stopped, while the crown pusher cycles among winding, date and hand-setting modes.
Carbon TPT, coloured Quartz TPT and precious-metal combinations give each version a different weight and visual texture. The McLaren W1 edition reshaped the case around the car partnership while retaining RMAC4. Because the model combines many pushers, seals and adjustable systems, a pre-owned inspection should test split and reset synchronisation, rapid winding, crown selection, date change, rotor setting and case integrity—not simply timekeeping.