The ETA 2378 is an automatic mechanical movement introduced in 1977. It is characterized by its thin design, incorporating features such as a date display and sweep seconds hand. The movement includes a micrometer regulator, two serially coupled barrels (one with a fixed spring and one with a slip spring), and is equivalent to the Lemania 8810 movement. The ETA 2378 offers automatic winding, a sweep seconds hand, and a hack feature. This reliable and intricate movement has been used since 1977.