A common feature of The Longines Saint-Imier Collection, a collection of exclusively mechanical timepieces, is the shape of the case, inspired by a 1945 model. There are several models available: the one in the photo is the Retrograde Moon Phases, 44 millimetres in diameter and powered by the automatic L707 calibre, developed ad hoc and made exclusively by ETA for Longines (A07.L31). On the silvered dial (there is also a black variant) are four retrograde functions, in addition to the day/night indications and the moon phases: the days of the week at 12 o'clock, the calendar and the second time zone with 24-hour scale on the right and left, respectively, and the small seconds at 6 o'clock. The case back is transparent sapphire crystal, the water-resistance rating is 3 atmospheres, and the strap is brown alligator leather, fastened with a folding clasp.
