The Helios FES 150 is a complete window installation kit designed for fitting all HVR 150 ventilation units, especially models with internal electric closures. It is suitable for mounting in single and double-glazed windows, thin walls, and panels. The exterior is protected by a flat rainproof grille with fixed lamellae, ensuring weather resistance and consistent airflow. The fan operation is managed through the included pull switch or an optional local switch, offering flexible control based on your setup.