This first produced model of this cupola was also the most numerous one.
GFM stands for Guet Fusil Mitrailleur (observation and machine gun). In the context of the Maginot Line, Cloche is French for an armoured cupola. The main visual characteristic of the cupola is the rectangular embrasures (3 to 5 in total).
For observation, an episcope (a miniature periscope), a periscope (there were several types available) or a bloc jumelle were used. Most GFM cupolas possessed a fitting in the top through which the periscope could be raised.
|1.70 m||1.60 m||0.20 m||10,5 t|
|2.70 m||1.60 m||0.20 m||17,0 t|
|2.70 m||1.80 m||0.30 m||26,0 t|
|2.15 m||1.70 m||0.25 m||17.0 t|
In some cases, when a GFM cupola was used as an auxiliary observation cupola for artillery, an observer could scan the surroundings with a periscope type J2 (enlargement 7x). In other cases, a type F1 (for PM) or F2 (for GM) were used (for less precise, general observation).
A characteristic feature of all GFM type A cupolas are the ear-like lifting points on each side. These were used to move/lift the cupolas into place during installation.