The base caliber for the two watches is the L1 (with the L2 adding a GMT function and day/night indicator) and it has one key feature that really sets it apart: a crown that you push to reset the seconds to zero and enter a time-setting mode. This means you never pull out the crown or fiddle with multiple positions. You simply push it in, set the watch, and push it again to set it in motion – it operates with a column wheel, in much the same way as the start/stop mechanism of a chronograph, with two discrete positions. The date is adjusted with a separate, dedicated pusher, and the GMT model uses a second crown to rotate the inner bezel used to mark the second timezone.

While the movements are made by Lehmann, finishing, casing, and final assembly are executed at Ernst Leitz Werkstätten on the Leitz Park campus in Wetzlar, Germany (just next door to the Leica factory). The finish on the movement is somewhat industrial, in keeping with the general vibe of the watches, but it's not careless – you're not seeing raw edges or unfinished plates, it's just not meant to be a flashy or showy caliber. The camera maker has no intention of setting up a full watch assembly and sees the partnership with Lehmann as a long-term one.