Power is delivered in the caliber 400 by two mainspring barrels, and the design of the gear train – including the gear teeth profiles, as well as that of the escapement – is intended to minimize energy losses due to friction and optimize efficiency. Oris says that the Caliber 400 delivers about 85% of the mainspring barrel torque, as opposed to an average of 70% in a conventional movement. This efficiency is enhanced by the use of a silicon lever and escape wheel, which interact with very low friction and which, of course, do not require lubrication (in this movement and others using the same solution, this contributes to better long term rate stability).
The movement, despite not using a silicon balance spring, has a total of 30 parts made of amagnetic materials, including the lever and escape wheel, as well as the axes of a number of critical components including the balance, escape wheel, and lever. All this means that the Caliber 400 is highly resistant to magnetism; it has been, says Oris, stress-tested to 2,250 gauss. The international standard for “antimagnetic” watches, says Oris, stipulates that for a watch to be called antimagnetic, it must exhibit a mean daily rate deviation of no more than ±30 seconds after exposure to a field with a strength of 200 gauss – the caliber 400 comfortably exceeds that, showing a variation in rate of only ±10 seconds a day after exposure to a 2,250 gauss field.