Cal. 48 is one of a family of chronograph movements produced by Landeron from 1937 through the 1970. In all, over 3.5 million examples were produced.

It is a 13.75 ligne movement with a cam switching chronograph system. a variety of 14 ligne variants were produced, as well as complicated versions with calendars, moon phase, and hour counters.

The preceding Landeron 47 movement (the first cam-actuated chronograph) featured three buttons Start, stop, and reset. Cal. 48 switched to two-button operation. But unlike most modern chronographs, where start/stop share a single button, Cal. 48 has one button (at 2 00) to start and a second (at 4 00) to stop and reset. A later revision of this movement, resulting in Cal. 149/189/349, features conventional start/stop button operation.

The original Landeron 48 featured a deep, curving hammer, a feature carried on to the 54, 56, and 58. The Landeron 51/151 features a conventional “boot” hammer, as does the 55, 57, 59/159, 80/180, and 81/181. The Landeron 148 moved to a distinct “JI” hammer shape, a feature shared by the 149/189/349, 154, 185, 186, and 187/248. Finally, the Landeron 152/352 moved to a deeply bowed hammer, a feature shared by the 153/353.

• Curved hammer
  • Landeron 48 - 13.75 ligne
    • Landeron 58 - Calendar
  • Landeron 54 - 14 ligne
    • Landeron 56 - Calendar
• “Boot” hammer
  • Landeron 51/151 - 13.75 ligne
    • Landeron 59 - Calendar
      • Landeron 159 - Calendar, date hand at 6 00
    • Landeron 80/180 - Different pusher layout, calendar
    • Landeron 81/181 - Calendar, moon phase
  • Landeron 55 - 14 ligne
    • Landeron 57 - Calendar
• “JI” hammer
  • Landeron 148 - 13.75 ligne
    • Landeron 185 - Calendar
    • Landeron 186 - Calendar, moon phase
  • Landeron 154 - 14 ligne
• “JI” hammer (revised) - Landeron stop/reset button
  • Landeron 248 - 13.75 ligne
    • Landeron 187 - Date
• “JI” hammer (revised) - Conventional chronograph operation (start/stop button)
  • Landeron 149 - 13.75 ligne
    • Landeron 189 - Calendar
    • Landeron 349 - Hour counter
• Bowed hammer
  • Landeron 152/153
    • Landeron 352/353 - Hour counter