1. Can be installed in all roof materials in roof pitches between 20° And 55° Or up to 65° With special springs 2. Modern design, special demension offered. 3. The sash can be opened max to 30 degree allowing easy cleaning and maintance 4. Aluminium flashing is durable and anticorrosive 5. Big ventilation allow the amount of fresh air flow into the room with window closed. 6. Easy to install, easy to use, feature complete system.