Landeron 11
The Landeron 11 and similar Landeron 13 was a chronograph movement produced in the 1940's by Landeron.
It is a compact 5-pillar column wheel monopusher chronograph movement measuring 13 ligne. Cal. 13 had a stronger mainspring.
Cal. 13 was also sold by Alpina as their Cal. 651 and Cal. 940.