* Suitable for: 2 modules, outdoors ? The blue housing is firmly connected to the subsurface or brick work. It can also be used to ensure easy installation in cavities: Drill opening, position housing and screw tightly in place; the retaining wings, which automatically swing out, secure the housing, while the plastic bars at the edge of the housing prevent it from sliding into the cavity. ? Required flushmounting opening: 117 x 218 mm (width x height) ? Permissible wall thickness for cavity installation: 7 to 27 mm