According to the Girard Perregaux website, the Constant Escapement L.M. offers a new and convincing solution to the watchmakers' age-old concern: the precision and regularity of the functioning of a mechanical watch. It took over eight years of research and development to firmly and reliably establish this system so as to apply an instant and continuous "constant force". Its name pays tribute to two emblematic figures of the company; its founder, Constant Girard-Perregaux, and Luigi Macaluso, who decided to promote this movement which was introduced as a working prototype in 2008. In brand new unworn condition, this is the first example ever offered at auction. What is constant forsce ? A constant force escapement incorporates a remontoire device to ensure constant force between the escape wheel and the balance. The escapement usually works in the following way: The upper escape wheel comes to rest on the pallet fork which is at the same level. When the balance returns, the anchor recoils which results in the application of pressure on the internal tensioning spring. The moment the pallet exits, this spring is released and transmits power to the lower escape wheel. This wheel then gives the impulse to the anchor. The small spring, therefore, gives an impulse force that is constant during the entire operation of the escapement.