Unidirectional Bezel (Standard) 

This model comes standard with a unidirectional rotating bezel (rotating counterclockwise only). This design originated from dive watches and prevents the bezel from being accidentally moved in the wrong direction. In the event of an unintended adjustment, the measured time can only be shortened, never extended. 

Bidirectional Bezel (Upgrade) 

Upon request, this model can be equipped with a bidirectional rotating bezel. This allows the bezel to be turned in both directions, enabling particularly quick and intuitive timing of intervals. This version is often preferred on pilot watches, as reference times can be set more quickly. The bezel can be turned directly to the desired position without having to take the longer route in the opposite direction, making operation especially convenient.