Calibre 400 Series movements are optimised for low torque (max torque of the mainspring less than half the torque of Calibres 110 to 115), for best efficiency and longevity. This is key to reducing wear and to getting to the 10-year recommended service intervals and 10-year warranty attributed to watches powered by Calibre 400 Series movements. We also introduced a new wheel design into the gear train that delivers far greater efficiency. Calibre 400 Series movements retain 85 per cent of the energy transferred from the mainspring, compared to a norm of around 70 per cent. This is reached through the selected combination of wheels and their tooth-profile. We spent a lot of time optimising the whole movement to get the best possible result for accuracy and longevity.