From Time + Tide:
"Longines has long occupied the entry-level luxury position in the Swatch
Group ladder, which means a step up in terms of movement specs over
brands like Tissot, Mido and Hamilton that mostly use the ETA C07, i.e.
ETA 2824 calibre variants. The Master Collection Small Seconds is
equipped with the L893.5, essentially a modified variant of the ETA A31,
with improved 72-hour power reserve and anti-magnetic components when
compared to the base calibre. The beat rate is 3.5Hz, and Longines did
dress up the movement somewhat, though I do think the Master Collection
Small Seconds would be a great example in an
argument for closed casebacks, especially if it would mean a
reduction in thickness."