Les Rochilles has a total of fice blocks, including two entrances. Here you can see the observation block with its observation turret. The turret is a so-called "cloche observatoire en éléments no. 2". This type is recognizable by its small size. It had the same embrasures as the cloche GFM, but because of its size you couldn't use a light machine-gun.

Les Rochilles is one the small works in the Alps that were built by the troops themselves with the help of engineers. The work had been designed by the offical design bureau, but they lacked the money to let it build by a civil enterprise. But despite the use of military labour the quality is still good.