The VP cupola (Vision périscopique = periscope only) was especially designed to be used in stand-alone interval observatory posts. However, the VP cupola was also used in observation posts close to and connected with ouvrages.
Because of the fact that the roof of the cupola was flush with the roof of the casemate it was build into, it was very hard to spot from a distance. The only thing that could give away it’s presence was when the periscope was in a raised position.
The hole in the top of the cupola could be closed with an armoured lid that was operated from inside.
The VP cupolas had two types of periscopes, type B and C. The type B periscope could magnify up to 12 times, type A 8 to 25 times.
The weight was 257kg, including the armoured cap.
Every VP cupola had two spare type P8 periscopes.
The type B and C periscopes were the most powerful observation units used at the Maginot Line.
In all, twenty VP cupolas were build and put in place.