It’s a system providing screening of door openings from insects. The mosquito - net wings are made of special aluminium profiles covered with a net and sealed at the bottom with the brush gasket. There are installed in the solid, practical, self-supporting aluminium door frames mounted in the door niche. That’s why the successful mounting depends on the correct measurements.  A hinged, single door mosquito - net is used for single doors and in case of double doors (niche wider than 160 cm) – a hinged, double door or sliding door mosquito - nets are used. 
The door frames of a sliding mosquito - net enables positioning of the wings and covers provided with brush gaskets.
The key factor in the installation is the correct door frame mounting in the niche, and what follows, the precise suspension (hanging in case of sliding doors) of the door wings.