Based on the 856 model series, designed as a functional instrumental clock in the tradition of our navigation clocks, the 857 model series, equipped with a pilot's bezel, also offers the option of measuring, monitoring or controlling memorization times. A decisive criterion, especially in aviation, and the reason for us to optimally design this important function. The aviator's bezel made of stainless steel , which can be rotated on both sides and locks in minute steps, is captively connected to the housing by a mechanism developed by us for this purpose. Like the watch case, the base of the ring is hardened using TEGIMENT technology. For the best possible readability, the lettering is applied in silver to an embedded, black anodized aluminum ring and provided with a luminescent triangle as the main marking. The pilot's bezel can be rotated in both directions and engages firmly and firmly in minute increments