Under the hood there is Longines caliber L888.2, a movement exclusively built for Longines by ETA (caliber A31.L01). It has a power reserve of 64 hours, which is quite a lot. Both Longines and ETA belong to the Swatch Group as you probably know, so Longines has a nice advantage of using ETA movements exclusively developed and produced for them. Since 1984, Longines has not been producing in-house movement nor do they want to (as you can read in the interview I did with Longines CEO Walter von Känel here), instead they use ETA movements but tadaaa… ones that are not being used by other watch manufacturers (within or outside the Swatch Group) in case of these exclusives. It doesn’t make the movements in-house, but in the end the result is more or less the same, exclusivity of specific movements.