High quality natural pinewood coated with impregnation and layers of water-based acrylic clear lacquer or white paint. The sash can remain open in any position up to an angle of 45°. Bottom handle for convenient operation. Ventilation flap and intergrated dust and insect filter. Maintenance-free exterior covers. Can be installed in roof pitches between 15° and 55°. Installation in roof pitches from 55° and 75° is possile, but specially manufactured springs must be ordered.