The Baume & Mercier 13750 watch movement, introduced in 1977, holds the distinction of being the thinnest automatic movement with a date and sweep second. It is eclipsed only by movements lacking either the date or sweep second functions, even as late as 2003. Featuring a micrometer regulator and two serially coupled barrels – one with a fixed spring and one with a slip spring – it is equivalent to the Lemania 8810 through 8818 movements. Notable functions of the Baume & Mercier 13750 include automatic winding, sweep seconds, quickset date, and a hack feature. It has been in use since 1977.