The Base for Flat Roof Size 355/400 offers a sturdy and reliable platform for mounting HR roof units on flat roofs. It ensures proper alignment and secure installation of ventilation equipment, supporting consistent airflow and system performance. Suitable for commercial and industrial buildings, this base provides a durable foundation that simplifies installation and maintains the stability of the HR roof unit. It is designed for long-term use, ensuring reliable operation and efficiency of the ventilation system.