When Bell & Ross first released the watch, the fact that the movement was a Sellita movement caused a sensation. There are two perspectives to consider this issue. The first is the added value of internal movement. My personal opinion is that "inside" is not a particularly useful metric for watch interest. Broadly speaking, the reliability, accuracy, structure and surface quality of motion can be evaluated. And, despite the symbolic significance of A. Lange & Söhne's internal movements, it is at least as important that they must be done so well, and are made from two viewpoints of craftsmanship and materials.