According to the standard, square flush-mount GES installation units can only be used indoors in dry rooms with dry-cleaned floors. They are installed in covers of underfloor device sockets and raised floors. Up to 14 service outlets can be installed. The minimum installation depth is 120 or 125 mm without a floor covering. Service outlets consist of a mounting support for the vertical installation of Italian-type installation devices, a carpet protection frame including mounting support insertion frames with ladders for stepped lowering of the mounting support in 5 mm steps to max. 20 mm and a hinged lid, which is captive and lockable in the carpet protection frame. The hinged lid possesses a stable pressure plate made of galvanised 4 mm sheet steel, a swivellable cord outlet with foam seal and a lowerable handle to open the cover. A recess in the hinged lid accepts the floor covering.