Inside the Heritage Classic – Tuxedo is the Caliber L893 link automatic movement, which is Longines' proprietary take on the ETA A31.501. The movement has a slightly off-beat frequency of 25,200 vph and an extended power reserve of 64 hours, and the escapement is fitted link with a silicon balance spring. You can't see the rotor for automatic winding or the modern escapement, though, since the back is kept closed. The caseback link bears the old-school Longines winged hourglass logo – tempus fugit.