EWT
The company presented in 2005 a proprietary development methodology called EWT (Experimental Watch Technology) to experiment, test and ratify their projects in-house. It's a proprietary research and development platform. It incorporates its own laboratory.
Two inventions current in EWT are the ‘Binomial’, a mono-material balance-and-spring wheel combination mechanism using isochronically stable materials, and the "Différentiel d’Egalité", a constant force device based in a spherical differential. This differential keeps providing the same constant force to all the four tourbillons, solving the typical problem where the main spring gives different amount of force depending on how much potential energy it retains.
Read more about this topic: Greubel Forsey